Design Report for a Hydrogen-Hybrid Miniature Locomotive

Transcription

1 Design Report for a Hydrogen-Hybrid Miniature Locomotive Institution of Mechanical Engineers Railway Challenge Prepared for: Institution of Mechanical Engineers: Railway Challenge Committee Prepared by: University of Birmingham Team June 2013

2 Prepared By: Robert Ellis University of Birmingham Team Gisbert Kapp Building Pritchatts Road Edgbaston Birmingham B15 2SA Prepared For: Institution of Mechanical Engineers Railway Challenge Committee 1 Birdcage Walk London SW1H 9JJ Great Britain Disclaimer: The work described in this report was undertaken by a team formed of students at the University of Birmingham. The work was carried out for the Institution of Mechanical Engineers Railway Challenge in 2013 and is intended for this purpose only. The opinions, data, and information presented in this report and at the Railway Challenge event are of the individual speakers or the team, and do not necessarily represent the opinion of the University of Birmingham or the University of Birmingham Alumni Circle of Influence by the University of Birmingham All rights reserved. Printed in Great Britain

3 Preliminaries Executive Summary This report is provided in support of the locomotive, designed by the University of Birmingham Team, which will participate in the Institution of Mechanical Engineers Railway Challenge in The document covers design, lists changes made since the original 2012 design, safety, and compliance with the Technical Specifications issued by the Institution of Mechanical Engineers. The locomotive uses hydrogen as its primary on-board fuel to provide a clean source of energy at the point of use, emitting just pure water. Hydrogen as an energy carrier can be considered sustainable if it is produced from renewable energy sources such as wind, wave or solar power. It also offers a higher energy density than diesel, enabling the locomotive to store 6 times the amount of energy required to meet the IMechE s energy storage targets, with provision to increase this to 18 times with additional tanks. Two 200 bar standard BOC gas tanks are used to store hydrogen for direct use in the fuel cell and carry replacement hydrogen. The locomotive was designed to utilise both standard BOC tanks as well as a custom built metal hydride tank that was used in the 2012 trial, the metal hydride tank is currently in use in other research but can be installed with little or no change to the locomotives operation. This dense, low pressure method of storage overcomes many of the safety concerns relating to hydrogen based transportation systems. Other key design features include: adjustable air suspension to satisfy the requirements for ride, the ability to capture and store braking energy (i.e. regenerative braking) both via direct battery storage and with the option of storing energy into a super capacitor bank to clearly demonstrate the locomotives regenerative capability. The locomotive has a dependable level of tractive ability, which in this version is controlled by a bespoke control system and operating software, coupled with the use of a Raspberry Pi microcomputer. Replacement of the original compact RIO has reduced the cost of manufacture significantly and provided a substantial technical challenge in providing a control system that was comparable to an industry standard device. The locomotive demonstrates that it is possible to construct an efficient, sustainable, safe and reliable hydrogen locomotive. Hydrogen storage locomotives are currently the focus of a number of rail projects, In particular there has been a recent interest in mining and industry related rail use. The Birmingham entry would suit this type of role well. It is hoped that this example and that set by industry and current overseas development of fuel cell technology will be adopted in the near future by the rail industry at large to address both climate change and fuel shortage issues. -ii-

4 Preliminaries Acknowledgements The team would like to thank the 2012 team for their continued input, suggestions and support. Without their decision to enter the trial competition, their dedication to completing the Hydrogen Pioneer and their vision of a clean, sustainable and innovative locomotive our team would have never gotten off the ground. In particular the team would like to thank Andreas Hoffrichter, for his research into hydrogen technology and the findings he contributed to the Hydrogen Pioneer project, we would also like to congratulate him on the completion of his PhD. We would also like to thank Stephen Kent for his suggestions and advice during the 2013 competition. Jon Tutcher for his significant creative input, advice on coding, wiring, user interface and his continued interest in the whole project. -iii-

5 Preliminaries Table of Contents Executive Summary... ii Acknowledgements... iii Table of Contents... iv List of Figures... v List of Tables... v Glossary of Terms / List of Abbreviations... vi 1 Introduction Background Information on the Team Design of the Locomotive Design Features Key Components Design Tools & Detailed Design Drawings Risk Analysis Hydrogen Safety Safety Related Operational Instructions Design Calculations Initial Design Validation Structural Calculations Dynamic Calculations Economic Considerations Conclusion References Appendices Appendix A: Team Members and Their Roles... 9:1 10 Appendix B: Bill of Materials (2013 build & original base locomotive materials) 10:1 11 Appendix C: Safety Analysis And Risk Mitigations... 11: Risk Mitigations... 11:1 12 Appendix D: Design Calculations... 12: Concept Design Calculations... 12: Track Twist Calculations... 12: Curving Performance Calculations... 12: Flange Clearance Calculations... 12: Flange Climb Calculations... 12:5 13 Appendix E: Construction Drawings... 13: Original Concept... 13: Frame... 13: Coupler... 13: Axle... 13: Lay Shaft... 13: Lay Shaft Mount... 13: Motor Mount... 13:7 -iv-

6 Preliminaries 13.8 Emergency Brake Mount... 13: Wheelset and Suspension Position... 13: Wheelset and new axle design... 13:9 14 Appendix F: Finite Element Analysis... 14:1 List of Figures Figure 1: Main Structural Frame... 5 Figure 2: Mechanical Drivetrain... 6 Figure 3: Raspberry Pi interfacing unit... 7 Figure 4: Raspberry Pi schematic diagram... 8 Figure 5: Raspberry Pi VNC server presentation... 8 Figure 6: SSH tool for Raspberry Pi terminal... 9 Figure 7: Pinging from the Raspberry... 9 Figure 8: Raspberry Pi, pinging the laptop Figure 9: Emergency circuit with Raspberry Pi connected Figure 10: Mbed controller in prototype stage Figure 11: Arrangement of Metal Hydride Tank and Fuel Cell Figure 12: Diagram of Proton Exchange Membrane Fuel Cell Figure 13: ReliOn E-1100 TM Fuel Cell System Figure 14: Hydrogen and Gasoline Fuel Leak Fire Comparison [2] List of Tables Table 1: Expenditure Account for Hydrogen-Hybrid Miniature Locomotive v-

7 Preliminaries Glossary of Terms / List of Abbreviations Term EECE IMechE PEM RSSB STP RP Explanation / Meaning / Definition Electronic, Electrical and Computer Engineering Institution of Mechanical Engineers Proton Exchange Membrane Rail Safety and Standards Board Standard Temperature and Pressure Raspberry Pi microcomputer -vi-

8 Introduction 1 Introduction 2013 marks the first year of the IMechE Railway Challenge. The success of the 2012 trial competition and the miniature locomotive developed by Birmingham University attracted a number of highly skilled and enthusiastic students to work on the new locomotive project. The majority of students working on this year s entry have used the locomotive in their research projects, and due to this interest have continued its development past their final examinations and completion of their final reports. The competition will fall shortly before graduation being the last and one of the most exciting team events that they will have taken part of during their university education. It is hoped that this project and competition will be a taster of what they can expect in an engineering career. This report describes the handover of the original Hydrogen Pioneer locomotive designed and built in 2012, the challenges that the 2013 team encountered and the modifications that the current team made to the locomotive in preparation for the 2013 Railway Challenge. The team and previous team were content with many of the original design elements and were keen to keep many of these in place, rather than design a train from scratch. Key features that were maintained were (1) use of a hydrogen fuel-cell, providing zero emissions and a high power density, (2) the existing frame and suspension system, (3) the battery power supply (4) the existing motors and motor controller. The significant changes to the 2013 version of the locomotive centre on (1) the design and implementation of a new control system, (2) the incorporation of a Raspberry Pi microcomputer, (3) a clear graphic representation of regenerated energy into the battery supply, as well as a cut off system powering down the locomotive once regenerative energy has been consumed, (4) an alternative storage system using a super capacitor bank to store regenerated energy to better comply with IMechE regeneration challenge rules. The report also demonstrates compliance with the specifications and rules as supplied by the IMechE Railway Challenge Committee. Version 2 specifications and performance are also indicated. 1.1 Background Information on the Team The team consists of mainly MSc. finalists based in the School of Electronic, Electrical and Computer Engineering. The Team is supervised and guided by members of Birmingham Centre for Railway Research and Education (BCRRE) as well as a handover member from the original team who is responsible for information continuity as well as offering invaluable advice and guidance. Team member roles and experience are documented in Appendix A:Team Members and Their Roles. -1-

9 Introduction The 2013 team is significantly smaller than the previous team. However, the original build that took place in 2012 required this larger team. The changes that have been made for the 2013 team have been put in place in a timely and efficient manner and as a result of working on an existing frame much of the frenzied process the 2012 team experienced has been reduced. Members experience and expertise mostly lay in electronics, software design and chemical engineering. As a result, when mechanical changes have been planned, an informal exchange of advice and guidance has been made available with the previous team members, in particular Stephen Kent, who was largely responsible for the original drive train and suspension design of the 2012 version. During the handover meeting in early 2013 an agreement was made that previous team members would not be directly involved but, would be available in a consultancy role. This has avoided a Too many cooks situation and has allowed for relevant and insightful suggestions. The team decided to keep with the original hydrogen fuel-cell power system. Sustainability is a principle ethos that Birmingham University promotes and members in the 2013 team are keen to adhere to. Also energy use reduction and resilience are personally very important, as well as key areas of research, to both PhD members of the team. The electric/hydrogen hybrid design is both innovative and likely to become common place in the rail industry in the near future, we feel that our contribution to this technology can forward its realisation. This team has substantially less pressure placed upon them in terms of not having to develop a full locomotive in the allotted time. This has allowed the development of more bespoke equipment for its function. The major benefit of this is the replacement of the compact RIO used in the original locomotive. Although an of the shelf product, its value and price to replace were significant, considerably increasing the cost incorporated in the locomotives design. The compact RIO was also required in a number of other research areas. The bespoke control system designed for 2013 was developed at less than 10% of the price of the compact RIO and is capable of communication between driver and motors, as well as data logging to a similar capacity as the compact RIO. From late 2012 onwards the locomotive has been used for team members MSc. study. This has allowed these students to be able to focus their efforts on both their research and the locomotive design and modification. Broadly there have been two teams focused on (1) developing and implementing a new control system and (2) improving drive efficiency and installing super capacitors. Both teams contribute to testing, Peter Fisher, designated handover team member, has been involved with all aspects of design and development, due to his involvement with the original team and knowledge of the locomotive related to his research. Team meetings were frequent, weekly from February onwards. During the Easter period the MSc. level students had an intensive examination, bench inspection and report period, resulting in the mid-march to mid-april period having no full team meetings. During this time, however, the control system team finalised their system for testing after this examination period. -2-

10 Design of the Locomotive 2 Design of the Locomotive 2.1 Design Features The locomotive as designed incorporates the following key features and benefits: Sustainable power the primary power source is the latest generation of hydrogen fuel cell, the only emissions being pure water, and the hydrogen can be generated using non-fossil fuel based technology such as renewables, e.g., wind or wave power. Inherently safe the design incorporates standard BOC 200 bar gas tanks for use in transporting and using hydrogen in a safe and reliable way. It has dual redundant emergency brakes, and fail-safe emergency brake application programmed into the control software, which is then overridden if necessary by the manual emergency buttons located on the frame and on a flying lead for the operator / driver. A large operating range the operating range exceeds that required by the Technical Specification The initial 2012 build featured a metal hydride tank that is currently not available to the team as it is needed in differing research projects. With that in mind the locomotive has been designed to allow connection and use of hydrogen tanks with varying pressures, 10 bar in the case of the metal hydride tank and 200 bar in the case of standard BOC tanks. This feature has allowed the locomotive to be displayed internationally whilst providing access to a convenient supply of hydrogen. To match the operating range of the original hydride tank three standard 200 bar tanks can be fitted in the same middle deck space, two inactive and one connected to the system. With the single metal hydride tank initially fitted, the estimated range when operating on a continuous 5 % gradient with a 400 kg trailing load is around 18 hours. High tractive effort all axles are powered in order to maximise tractive effort, the design includes scope to add ballast as required, and the system can easily be developed to include traction control (all of the components required are fitted, but there was insufficient time to develop the required software). As a result of decreased mass resulting from the decision to use 200 bar hydrogen tanks and not the metal hydride tanks, ballast can be added to increase the locomotives mass to maintain the high tractive effort. High efficiency the motors selected are high efficiency permanent magnet designs with carefully matched motor characteristics, the drivetrain is based on highly efficient chain drives, and the motors and traction controller provide regenerative braking. -3-

11 Design of the Locomotive Excellent ride quality and minimum track forces the design has an adjustable air suspension system that can be quickly and easily finetuned both in terms of stiffness and damping to optimise ride and minimise track forces. Long and reliable service life the peak traction loads are met by the lead acid batteries, which are topped up by the hydrogen fuel cell thereby maximising fuel cell life. The drivetrain components are proven in mainline service on track inspection trolleys rated for kg loads, and the control system is based on a rugged and reliable industrial computer platform. Straightforward manufacture A combination of off the shelf components with a low price but highly reliable bespoke control system that would be easy to replace and reproduce. Mechanical changes were made by the team in the department workshop or with the assistance of the workshop technician. There was a close focus on what could be done in house, using available components to minimise cost. Flexible application the gearing ratio can be easily adapted to provide the ideal balance of speed and tractive effort. The extruded aluminium frame can be easily reconfigured for different loading gauges, and the wheelset and drivetrain arrangement can be easily adjusted to suit different track gauges. Low cost The 2013 model has a significant reduction in cost whilst reliability and performance have not been reduced. This is mainly as a result of the replacement the high cost compact RIO control system and the metal-hydride tank. A list of the major materials and components used in the construction of the miniature locomotive can be found in Appendix B: Bill of Materials Frame 2.2 Key Components The locomotive frame is constructed with extruded aluminium beams, which support each of three decks. The bottom deck supports the batteries, traction motors, and drivetrain, and incorporates a heavy duty steel plate upon which these components are mounted. The middle deck supports the metal hydride tank, up to three can be accommodated, and the top deck supports the fuel cell and control electronics. The body panels are constructed from heavyweight clear plastic sheets, to allow viewing of the internal components, which are secured to the extruded aluminium beams using a simple arrangement of slots and bolts. -4-

12 Design of the Locomotive Figure 1: Main Structural Frame The main frame is 640 mm wide, maximising internal space and minimising overall wheelbase length in order to improve curving performance. These dimensions are currently configured to meet the loading gauge requirements of the Stapleford Miniature Railway, but could easily be re-configured for other loading or track gauges if required. The vertical load is transmitted directly from the wheels, up through the suspension to the main beam supporting the middle deck. This load is then distributed three ways: down to the lower deck, which supports the batteries and traction equipment; sideways to support the metal hydride tank; and upwards to support the upper deck with the fuel cell and control equipment. The use of three decks enables the high current / high voltage equipment, on the lower deck, to be physically separated from the metal hydride tank on the middle deck Motors & Drivetrain Each of the two permanent magnet motors generates 4 Nm of torque, which is transmitted via an efficient and easily configurable series of sprockets and chains to a lay shaft. This in turn transfers drive to both wheels on each axle. The use of the lay shaft facilitates the required gearing ratio for this application, and because it is positioned in line with the pivot point of the radial arms, it also ensures that chain tension remains constant regardless of suspension movement. -5-

13 Design of the Locomotive Motors Lay shaft Sprockets Chains (blue lines) Figure 2: Mechanical Drivetrain Other features of the drive system are: a duplex chain between the motor and lay shaft in order to minimise wear on the relatively small sprocket on the traction motors; rubber mounted axles, which provide increased ride comfort, allow for unequal vertical movement of the suspension left to right, and give a degree of radial flexibility to improve curving performance. The choice of a fixed axle with wheels mounted on individual bearings provides for simpler wheelset construction, easily adjustable track gauge, and makes provision for independently driven wheels, should enhanced curving performance be required for other applications Braking System The braking system consists of two independent braking systems: (1) Mechanical brakes mounted to both traction motor shafts, primarily for use in emergencies and capable of stopping the train under all eventualities, and (2) a dynamic service brake, which uses the traction motors as generators, using braking energy to re-charge the batteries. The new control system in place provides an improved smooth deceleration rate. It is thought that this will provide a much smoother ride, which can also be tailored to produce increased stored energy whilst braking. Due to time constraints in the original 2012 design control software, although functional to a safe and reliable manner, was not developed to the point where the team were fully satisfied. It is hoped that the new software control system will address this issue. Please note that the mechanical emergency brake is a well proven commercial design used on mainline track inspection trolleys rated for kg loads. -6-

14 Design of the Locomotive Electrical & Control System The main components of the electrical design are: two high efficiency permanent magnet DC motors, which are connected to a single motor controller (capable of regeneration); four calcium based lead acid batteries with a combined capacity of 4.3 kwh; A Raspberry Pi (RP) microcomputer for use in wireless communication between operator and motor controller; a bespoke control system with two Mbed processors, responsible for communication between the RP and motor controller as well as logging data and diagnostics; and a cutting edge fuel cell with in-built diagnostics. The traction drive system operates at 48 V DC, in order to minimise traction currents and cable losses, the control computer and emergency control system operate at 24 V DC, and various other instrumentation and control components operate at 12 V DC. In service braking mode, the electric motors act as generators and the resulting power is stored in the batteries. Figure 3: Raspberry Pi interfacing unit Raspberry Pi is a simple low cost credit size computer which is capable of interfacing with many different devices at a time. The Raspberry Pi is used to replace the National instrument computer due to differing research projects requiring the NI machine. The Raspberry Pi has an Ethernet port which is ideal for the locomotive system. The Raspberry Pi provided many different options to interface, such as general purpose input output pins, USB ports and 2 different video output ports. The general purpose input output pins allows the system to interface with the Raspberry Pi in different methods such as Inter-Integrated Circuit (I 2 C), serial and Serial Peripheral Interface. The dual USB ports on the Raspberry Pi can allow USB devices together without any integration issues. -7-

15 Design of the Locomotive Figure 4: Raspberry Pi schematic diagram The Figure above shows the systems available on the Raspberry Pi and roughly the location of each system. The RP works via Linux operating systems which are very efficient when used for communications. RP provides a great platform for various coding languages such as C, C++, Python, Java and Perl. It uses an SD card to run, as a result the system can be updated or settings can be changed very quickly. The Raspberry Pi works with a five volt supply which is provided through the micro USB cable. The Raspberry Pi is directly connected to the router through the Ethernet cable connection. Once the Raspberry Pi is connected to a router it can be controlled entirely through a laptop connected on the same server. The two methods to use the Raspberry Pi is SSH tool or using a VNC server. The VNC server allows the entire Raspberry Pi to be presented onto the other laptop as it is shown in the picture below. Figure 5: Raspberry Pi VNC server presentation The SSH tool provides a similar purpose but this time a terminal is opened and commands are sent. -8-

16 Design of the Locomotive Figure 6: SSH tool for Raspberry Pi terminal The RP once linked onto the network allows the driver to communicate with the locomotive wirelessly. The Wi-Fi connection provides a fast and secure method which can be used to process data quickly and with great stability. The key issue remains is the case in which a Wi-Fi communication is lost. In such cases the locomotive must come to a halt immediately and shouldn t respond until or unless the laptop is connected back. To solve this problem a code in python is written which continuously pings the laptop connected to the router. This code is implemented into the Raspberry Pi, every time the system starts up it runs this program. To ping the laptop it requires the laptop IP which is stored in the code. The process of pinging the laptop is shown below in form of a flow chart. Figure 7: Pinging from the Raspberry Some section of the code is explained below. -9-

17 Design of the Locomotive Figure 8: Raspberry Pi, pinging the laptop A while loop runs forever which keeps continuous check on the connection status. If the connection is good the output on pin 17 is set high which keeps the locomotive circuitry running perfectly. The if statements allow the system to check whether the output needs to be high or low. The output from the Raspberry Pi is used to control the emergency circuit. As the output goes low due to los of laptop connectivity the system comes to a halt with keeping the control system independent of this process. The Raspberry Pi provides a five supply hence to control the system of 24 volts system a transistor was needed to be connected which is shown in the circuit below. Figure 9: Emergency circuit with Raspberry Pi connected The Raspberry Pi isn t used for any controlling system. The microcontroller used in the later stages is controlled using the SSH tool and Raspberry Pi does the interface for the system. The system works as per required. The picture below shows the microcontroller messages being received and controlled through the Raspberry Pi. To control the system a real time processor was required. Raspberry Pi can be used to control the real time processing but it lacked few points which forced us to look into other devices to do the entire real time processing. Raspberry Pi provided only few GPIO pins which could not be used to connect all the devices. The coding needs to be done in python which required more time learning new languages. By using different devices for performing real time processing made the task of processing easy, many different languages were an option now. The devices which were considered as an option were Mbed, Arduino and PIC. As Mbed works at the fastest speed and provide many different features such as multiple communications such as 3 UART. -10-

18 Design of the Locomotive The Mbed uses C++ programming to be coded in. The great feature provided by C++ programing is the formation of libraries which allows the main code to be simple and straight forward. The Mbed is connected to the motor controller, Tachometer, Xbee, SD card and the GLCD. The first communication is established between the Mbed and the Raspberry Pi. The USB port on the MBED allowed direct connection with the Raspberry Pi. To complete this connection a lot of coding wasn t required. The system was coded to send serial messages through the USB cable to Raspberry Pi. Figure 10: Mbed controller in prototype stage The final monitoring system includes various safety systems such as heat detection and battery charge status, and provides information on the amount of energy that is regenerated during braking. These safety features began to have an excessive demand on the Mbed s processing capacity and resulted in damage to a number of early prototype components, as well as loss of motor control. As this was essential to address, the bespoke control system was redesigned with a second Mbed processor. The added processing capacity allowed for reliable motor control and safety monitoring, producing a more robust system. Once testing gave satisfactory and continuous control results the control system was rebuilt into a more sturdy design fitted into and enclosure. -11-

19 Design of the Locomotive Hydrogen System The University of Birmingham has several decades of experience in hydrogen related research, with dedicated groups in the Schools of Metallurgy and Materials, Chemical Engineering, Chemistry and the Department of Economics. The university runs a number of hydrogen powered cars as well as a hydrogen powered canal boat, and this experience has been drawn upon in order to develop the hydrogen system on the locomotive. The locomotive uses a hydrogen stored at low pressure (10bar) in a standard BOC tank and a fuel cell, both described below. Fuel cell BOC 200 bar Hydrogen tank Figure 11: Arrangement of Metal Hydride Tank and Fuel Cell The BOC hydrogen tank is located on the middle deck and secured on rubber lined wooden supports using ratchet straps. Stainless steel braided flexible hosing is used to connect the tank to the gas supply panel, located to the rear of the top deck, which controls the supply of hydrogen to the fuel cell Fuel Cell The most efficient technology to convert hydrogen to electricity is fuel cells. The most suitable fuel cell for this project is the Proton Exchange Membrane (PEM) fuel cell, as it operates at low temperatures and has a fast start up time. In a PEM fuel cell, hydrogen (H 2 ) is split into two protons (H + ) that diffuse across the electrolyte membrane, whilst the two liberated electrons travel around an electrical circuit. The protons, electrons and oxygen combine with oxygen (typically from the air) to release water. This process only forms water, electricity and heat, see Figure

20 Design of the Locomotive Figure 12: Diagram of Proton Exchange Membrane Fuel Cell The fuel cell used for the locomotive is a ReliOn E-1100 TM which is commonly used as an uninterruptable power supply (UPS) for markets such as the telecommunications industry. It is designed for the continuous supply of 1.1 kw and powers a 48 V DC system, as used on the locomotive. Figure 13: ReliOn E-1100 TM Fuel Cell System The unit incorporates various control and status monitoring systems and this simplifies the installation and operation of the unit. It requires no regular maintenance, and with peak loads being met by the on-board batteries, it is expected to provide many years of trouble free service. -13-

21 Design of the Locomotive 2.3 Design Tools & Detailed Design Drawings The original concept drawing for the vehicle is shown along with a full set of detailed design drawings in Appendix E: Construction Drawings. The concept was to provide an easy to construct frame that incorporated radial arm air suspension, was as short as possible to improve curving performance, and had a low centre of gravity to ensure adequate stability. The final design was put together using a number of software tools including 3D CAD (Solid Works) to assist with both design and structural calculations. The diagrams reproduced here are taken from the original 2012 design and where no modifications have been made is highlighted. Sections of the drive train which have been modified for the 2013 competition are also noted. Appendix E: also shows the development and design of the bespoke control system. The initial concept was to provide a reliable and robust system of control that would replace the high end compact RIO industrial computer initially in use in Based on a department wide interest in the useful implementation of a Raspberry Pi (RP) microcomputer the compact RIO was removed and the control system team began work on using and RP in this role. It was quickly realised however that the RP had a number of limitations that were primarily related to a lack of full compatibility between the RP and the RoboteQ motor controller as well as real time control. The limited processing power in the RP mean that data monitoring and logging is not possible. As a result the RP was incorporated as a means of wireless communication with a purpose built control system. This new system, although initially very challenging to bring up to an operational level, is reliable and extremely cheap to reproduce. -14-

22 Risk Analysis 3 Risk Analysis Both a top down and bottom up risk analysis were undertaken by members of the team, including members from each of the project teams. The results of this analysis are contained in [1]. It can be demonstrated that a wide range of risks have been considered in the design of the locomotive and mitigation measures have been included in the design. It is appreciated that one of the main hazards is the use of hydrogen as the energy storage medium, and further detail about hydrogen safety is presented below. 3.1 Hydrogen Safety The primary hazard with hydrogen is a large concentration in an enclosed space. This can result in suffocation for persons within that space, or can cause an explosion in the event that a source of ignition is present. However, hydrogen is lighter than air and, unlike fossil fuels, it dissipates quickly unless trapped. With this in mind, the design of the locomotive is well ventilated to prevent an accumulation of hydrogen. While hydrogen is explosive, it requires a concentration of 4 % volume hydrogen to air in order to ignite, a concentration four times higher than that for gasoline. It is also important to note that the result of hydrogen combustion is water, and no toxic fumes are released. Radiant heat is also significantly lower during hydrogen combustion compared with petroleum based combustion, meaning that in the event of a fire, bystanders will have reduced risk of injury if the event happened in their proximity [2]. Indeed, a study by the University of Miami has shown that hydrogen is safer than gasoline in case of a fuel pipe leak as shown in Figure 7. Figure 14: Hydrogen and Gasoline Fuel Leak Fire Comparison [2] The first image shows the flames 3 seconds after ignition for a hydrogen car (to the left) and a regular gasoline car (to the right). The second image shows the flames 1 minute after ignition (again hydrogen to the left, gasoline to the right). This demonstrates that hydrogen is safer than gasoline in such circumstances. -15-

23 Risk Analysis After successful tests using compressed hydrogen tanks showed there was no discernible difference in performance, providing that the larger mass of the hydride tank was accounted for, it was decided that it would be more convenient to use standard 200 bar tanks rather than the significantly more expensive and unique metal hydride tank. This choice was made partly as a result of the restricted availability of the metal hydride tank and the substantial increase to cost it would represent if the locomotive was being put into production. It was decided during the 2012 build that the metal hydride tank was safer than 200 bar tanks as a result of lower pressure containment, 10 bar. This reduced the risks of high pressure leaks, leading to a faster explosive mixture volume (4%) and less likelihood of the tank acting as a projectile. However, the BOC tanks are used in many areas of industry and transportation, in fork lift truck propulsion (where hydrogen use is on the increase) and outside hot air heating systems (differing gasses being used). During testing we have altered our risk assessments to accommodate BOC tanks, following the necessary precautions laid out in their own guidelines. The team accept that there are dangers associated with the use of hydrogen, but feel that these concerns should be placed on all fuels that are used in autonomous locomotive systems and that hydrogen should not be singled out. -16-

24 Safety Related Operational Instructions 4 Safety Related Operational Instructions There are a number of important safety related operational instructions which must be observed when operating the locomotive: A hand held sniffer shall be used to inspect the vehicle prior to operation on a daily basis as any leak of hydrogen is potentially dangerous should hydrogen be detected, the vehicle shall not be operated until such time as the source of the leak is identified and rectified. A soap test shall be administered to hydrogen the steel braid connector joints and other joins in the hydrogen piping system, the presence of bubbles will also assure possible hydrogen leaks are discovered prior to operation. Only hydrogen safety qualified members of the team shall connect and handle hydrogen. The pressure in the air suspension shall be checked on a daily basis prior to operation and shall be within 5 psi of the recommended pressure to ensure even wheel loading and sufficient ability to cope with track twist faults. Work may need to be undertaken on the locomotive during the testing and commissioning phase, and a visual inspection should be undertaken prior to operation to verify that no tools or debris are left inside, as these could potentially interfere with correct operation or cause a short circuit. Prior to operation it should be ensured that the emergency brake manual release lever is in the correct position (i.e., NOT in the towing position) as the emergency brakes cannot be applied if this lever is set incorrectly. The emergency brake must be operated prior to any coupling / decoupling activity taking place in order to prevent the operator from being crushed by any unintentional movement of the locomotive. Prior to hydrogen use, a battery only test run should be made, this will allow the driver to become more accustomed to the unfamiliar track, as well as enabling an electrical systems check with reduced hydrogen associated risks. Failure to observe the above could cause the locomotive to fail, or result in injury to operators, staff, passengers, or the general public. -17-

25 Design Calculations 5 Design Calculations (Section 5 has been reproduced using data and report documentation submitted in the 2012 challenge report Authored by Stephen Kent calculations shown in Appendix D are also reproduced except where indicated) 5.1 Initial Design Validation The design concept was informed and verified by a number of calculations to establish various key aspects of the locomotive s design as follows: tractive effort requirements, gearing ratio, and drivetrain efficiency; Likely vehicle mass and mass requirement to ensure adequate traction in all; operating conditions energy storage requirements. Mass additions to restore metal hydride tank mass. These calculations are summarised in Appendix D: Design Calculations, and demonstrate that the vehicle has ample tractive effort to haul the required load, is sufficiently heavy to ensure that the tractive effort can be reliably transmitted to the rail, and has more than ample energy storage to meet the requirements of the Technical Specification. These calculations were revised as the design progressed to ensure the locomotive would continue to meet the required key performance requirements. 5.2 Structural Calculations The locomotive needed to have considerable mass in order to provide sufficient tractive effort. Therefore, the approach taken to the structural design was to over specify key frame and mechanical components as weight was not an issue. This included the following: high grade, over-sized aluminium sections for all framework; extensive gusseting in both lateral and vertical directions; machine grade steel for all suspension and axle supports; oversize axles and lay shafts; a heavy steel baseplate to support batteries and motors; Proven drivetrain components including wheels, transmission, motors, and emergency brakes rated for kg. Finite Element Analysis was undertaken on key structure elements of the frame (based on the 3D CAD model) to ensure that the core elements of the frame are indeed of sufficient strength. This analysis, shown graphically in Appendix F, demonstrated that the load on the frame is well within the maximum allowable for the materials used. -18-

26 Design Calculations 5.3 Dynamic Calculations A number of checks were performed to verify that the dynamic performance of the locomotive would be acceptable as described below, and the detailed calculations are shown in Appendix D: Design Calculations Track Twist The tolerance of the design to track twist faults was established through a series of calculations. The worst case track twist in the Technical Specification is 6 mm of twist per 0.25 m of track. This was done by firstly calculating the pressure required in the air suspension for 25 % suspension sag and then estimating the change in this pressure were a worst case twist was to be applied to the vehicle. Assuming an even wheel loading, which the design has been careful to achieve, the ratio of pressures provides an accurate prediction of wheel offloading. The calculations in Appendix D: Design Calculations: 12.2 demonstrate that the worst case twist fault will result in approximately 16.7 % wheel offloading, which is well within the 60 % maximum specified Curving Performance The clearance required to enable the locomotive to negotiate the tightest specified curvature was also calculated. As shown in Appendix D: Design Calculations: 12.3, this was done by firstly calculating the versine for a vehicle with a 1.25 m wheelbase on a 20 m curve, and then using this to calculate the angle of attack at a leading wheelset as shown in Appendix D: Design Calculations: This angle of attack was then used to infer the lateral offset between the central axis of the wheelset and the leading edge of the flange. This offset was calculated to be 1.7 mm per side, equating to a total required flange clearance of 3.4 mm. The wheelsets have been manufactured in accordance with the Technical Specification and have a back to back spacing of 242 mm and a flange width of 5.6 mm, as advised in a response to Q&A Number 9. Given that the track gauge is 10¼ inch (260 mm), this gives the locomotive a flange clearance of just over 6 mm, i.e. sufficient for the tightest curves. It is also noted that gauge widening has been applied to the tightest curves, giving an extra 6 mm of flange clearance (i.e. approximately double that which the locomotive requires) Flange Climb The limiting ratio for lateral to vertical load on wheels is defined by Nadal s Limit, which is calculated based on the coefficient of friction between wheel and rail (at the flange) and the flange contact angle. This formula is generally accepted to be pessimistic as it assumes a high angle of attack, which is not necessarily the case. -19-

27 Design Calculations However, the calculations shown in Appendix D: Design Calculations: 12.5 demonstrate that, assuming a worst case wheel rail friction coefficient of 0.6, the maximum safe lateral load according to Nadal s Limit is 878 N. Using equations of circular motion, the predicted lateral load per wheelset, assuming that all of the lateral load is borne by the outside wheel (i.e. the worst case scenario), is predicted to be 130 N, i.e., less than 1/6 th of Nadal s Limit. -20-

28 Economic Considerations 6 Economic Considerations A comprehensive bill of materials is presented in Appendix B: Bill of Materials. The bill details all components used in the construction of the locomotive, except minor mechanical fittings, such as nuts and bolts, or some electrical components such as low power cabling. As much of the base locomotive was in place at the start of the 2013 project it assumed that cost breakdown for this year was made based on a new locomotive being developed and constructed from scratch. However, as the base locomotive had already been designed it is assumed that the 2013 team are constructing from designs that already existed. As a result, construction costs will be representative of a scratch built locomotive but design element costs will only cover additions and developments made by the 2013 team. The replacement of the industrial computer and the choice of using pressurised hydrogen rather than a metal hydride tank allowed significant savings to be made. Component cost based on the cost to reproduce the original base locomotive (minus compact RIO and metal hydride tank) with the additions made by this team is estimated to be no more than 12,000. As much of the design and construction of the 2013 project has been undertaken as part of research projects their human resource cost is assumed to be zero, a secondary figure for total cost is given which assumes a paid team conducted the design and development. Table 1: Expenditure Account for Hydrogen-Hybrid Miniature Locomotive Cost Position Number of Man 20 per Hour Cost in Hours Project Management Meetings Design Mechanical Electrical- and Control System Hydrogen System Total Design Construction Mechanical System Electrical System Hydrogen System Total Construction Testing Total Human Resources (if work paid ) Component Cost Total Cost of the Project Total Cost of the Project with paid human resources

29 Economic Considerations The locomotive construction for 2013 has considerably less costs associated with it than the original 2012 version. As this is a student led project human resource cost is a minimum, however if the locomotive had been designed and constructed by an independent company cost would be similar to the previous year s entry, some This is especially important when considering an application for the locomotive if it were put into production. With a Finalised production design and industrial construction process the man hours involved in mass production would be expected to fall. As a result it is assumed that mass production could be achieved for As with the findings of the 2012 model, this figure is still considerably higher than a fossil fuel based locomotive with similar performance. Both fossil fuel and fuel cell powered locomotives are effective traction systems in areas that lack electrification, diesel in particular, has proved it s self in this role for a number of years. And with the introduction of diesel hybrid trains such as the KiHA E200 in Japanese there seems to be little reason for adopting a technology such as hydrogen fuel cells when cheaper established technology is available, even when a hydrogen powered train may perform favourably. As a result the 2013 team began to look at applications for the hydrogen locomotive that would outperform fossil fuel powered locomotives in most cases. The main appeal for this technology is the lack of harmful emissions, the possibility of making hydrogen from other renewable sources, and the relative safety of low pressure hydrogen transportation. It was decided that an ideal function for the 2013 locomotive would be in an underground setting. This could be anything from the mining industry, underground construction and even the possibility of underground transportation. It is thought that the savings in infrastructure development would more than offset the potential costs involved in construction of a locomotive unit. The ability to be able to operate for many hours without electrification would remove the need for high clearance in mining and underground tunnels. The result being smaller tunnels could be designed and implemented at a fraction of larger tunnel costs. As well a reduced need for extensive tunnel purification systems, designed to remove fossil fuel exhaust emissions, could be adopted. Indeed this seems to be a move that is currently being adopted in a number of large scale mining operations in South Africa and Indonesia [3], with a similar mining locomotive in development at Vehicle Projects, Denver [4]. The team feel that the Hydrogen Pioneer is in a position that it could readily be developed for use in an underground setting with little modification. As this competition develops it is hoped that future teams will develop the potential of the locomotive for use in zero emission public transport. The mass production of the hydrogen related components will drive cost down, and the cost of hydrogen gas is also expected to fall, as its use becomes more widespread, and in some areas e.g., Los Angeles, large consumers of hydrogen pay already less than for the equivalent diesel. Indeed, studies have shown that hydrogen powered commuter railways can be more economic on a life cycle and implementation cost basis compared to the electrification of the commuter lines [5] [6]. -22-

30 Conclusion 7 Conclusion The main focus of the 2013 locomotive team has been to design and implement a low cost alternative to the compact RIO installed on the original Hydrogen Pioneer. This has been achieved successfully. Super capacitors have been implemented to address the issues with the trial year regeneration test, but we also hope to demonstrate the regenerative ability of direct battery charging via regenerative braking. The team is confident that these adjustments incorporated into the original base locomotive will demonstrate the potential of hydrogen as an efficient, clean and viable fuel that could realistically be in widespread use in the near future. -23-

31 References 8 References [1] M. Swain, Fuel Leak Simulation, Coral Cables, FL: University of Miami, [2] A. Hoffrichter, Hydrogen as an Energy Carrier for Railway Traction, University of Birmingham, Birmingham, [3] P. Moore, Mining Locomotion, Underground Rail, [4] Vehicle Projects INC, Vehicle Projects INC, [Online]. Available: [Accessed 20 May 2013]. [5] I. Dincer, Environmental and sustainability aspects of hydrogen and fuel cell systems, International Journal of Energy Research, vol. 31, no. 1, pp , [6] G. D. Marin,. G. F. Naterer and. K. Gabriel, Rail transportation by hydrogen vs. electrification, Case study for Ontario, Canada, II: Energy supply and distribution, International Journal of Hydrogen Energy, vol. 35, no. 12, pp ,

32 Appendices Appendices Appendix A: Team Members and Their Roles Appendix B: Bill of Materials Appendix D: Design Calculations Appendix E: Construction Drawings Appendix F: finite Element Analysis -25-

33 Appendix A: Team Members and Their Roles 9 Appendix A: Team Members and Their Roles Name Study Role Peter Fisher PhD Hydrogen Fuel specialist - Drive train design - supercapacitor integration design handover team member Kamil Hashmi Amreen Ahmed Mahdieh Bagheri MSc MSc MSc Control design and integration - software design and integration Control design and integration - electrical component fabrication - operation testing Hydrogen fuel testing - battery cycling testing - mechanical engineer Robert Ellis PhD Project Management Stuart Hillmansen N/A Supervisor - design adviser -9:1-

34 Appendix B: Bill of Materials (2013 build & original base locomotive materials) 10 Appendix B: Bill of Materials (2013 build & original base locomotive materials) IMechE Railway Challenge - Bill of Materials Authors: J Tutcher & S Kent Issue Date: 12 June 2012 Area Part / Assembly Assemblies Required Drive train Detail / Parts Per Assembly Numbe r Per Assem bly Total Requir ed Supplier Wheel 4 Wheel 1 4 Donfabs & Consillia 20mm bearing Insulator pads 22 tooth sprocket 2 8 Donfabs & Consillia 2 8 Donfabs & Consillia 1 4 Donfabs & Consillia Steel dowels 2 8 Donfabs & Consillia Bolts 4 16 Donfabs & Consillia Bolt retainers Axle 2 Made from 26mm diameter steel rod Axle support 8 5mm steel plate Rubber shaft lining 4 Handlebar grips Spacer washer 40 M20 flat washer 2 8 Donfabs & Consillia 1 2 RS Compone nts 1 8 RS Compone nts 1 4 Chain Reaction Cycles 1 40 RS Compone nts Simplex chain mm 1 4 Donfabs & Consillia -10:1-

35 Appendix B: Bill of Materials (2013 build & original base locomotive materials) 13 tooth sprocket 4 15mm bore 1 4 Donfabs & Consillia 60 tooth duplex sprocket Lay shaft 2 Made from 15mm diameter steel rod Lay shaft support bearing 2 15mm bore 1 2 Donfabs & Consillia 4 12mm diameter pillow blocks 1 2 RS Compone nts 1 4 RS Compone nts -10:2-

36 Appendix B: Bill of Materials (2013 build & original base locomotive materials) Frame Hydrogen System 11 tooth duplex sprocket 2 12mm bore 1 2 Donfabs & Consillia Duplex chain 2 1 metres 1 2 Donfabs & Consillia Emergency brake 2 Emergency brake 1 2 Donfabs & Consillia 2 Adapter for motor shaft 1 2 Donfabs & Consillia Traction motor 2 LEM with special shaft 1 2 Lynch Motor Company Traction motor support Emergency brake support Aluminium frame (60 x 60 aluminium extrusion) 2 8mm aluminium plate 2 8mm aluminium plate 1 200mm uprights 1 2 RS Components 1 2 RS Components 4 4 Bosch Rexroth 230mm 4 0 uprights 250mm 4 4 Bosch Rexroth suspension arms 520mm cross 8 8 Bosch Rexroth members 1500mm 4 4 Bosch Rexroth beams 800mm 2 2 Bosch Rexroth beams Hinges 4 60mm 1 4 Bosch Rexroth Gussets 24 60mm 1 24 Bosch Rexroth Baseplate x 900 x 4mm steel plate 1 1 Arnold Steel Suspension 4 Manitou Swinger Air Shock 1 4 Chain Reaction Cycles Suspension 16 5mm steel 1 16 RS Components supports plate Suspension bolts & 8 M8 1 8 Screwfix nylocks Nylon spacers 16 n/a 1 16 RS Components Fuel cell 1 Relion 1.1kW 1 1 Hoppecke Fuel tank bar 96x BOC tank Gas supply panel 1 n/a 1 1 Hoppecke Tank supports 2 From 30 x Wickes timber Tank straps 2 Ratchet straps 1 2 Screwfix Tools Air suspension 1 n/a 1 1 High On Bikes -10:3-

37 Appendix B: Bill of Materials (2013 build & original base locomotive materials) Electric Power Supply pump 12V leisure batteries 4 90 amp hour 1 4 Tanya Limited Control System Regeneration system High current cabling 12 1 metre RS amp cable Traction controller 1 Roboteq HDC Active Robots Control computer on 1 Raspberry Pi 1 1 RS train Real time processor 2 Mbed 1 2 Farnell Software 1 Ubuntu 1 1 Ubuntu DC/DC converter 1 10/p, 15W, 1 1 Onecall/Farnell 5V Enclosure 1 45x30x RS cm DC/DC converter 1 48 V to 24 V 1 1 Traco Power Emergency stop buttons Schreider Electric 5 bank Relay RS Supercapacitor bank 1 400F 2.7V 25 1 Onecall/Farnell capacitor Diode 3 100A 2 6 Onecall/Farnell Contactors 2 24V 180A 1 2 ADR/Toolbox Signal relays N/A Part of N/A N/A N/A control system Original build materials remaining in the 2012 entry 2013 entry build materials -10:4-

38 Appendix C: Safety Analysis And Risk Mitigations 11 Appendix C: Safety Analysis And Risk Mitigations 11.1 Risk Mitigations IMechE Railway Challenge: Top-Down Safety Analysis and Mitigations Author: Peter Fisher, Syed Kamil Hashmi, Robert Ellis Issue Date: 14th of June 2013 Risk: Killed or Injured Derailment Flange Climb Angle Attack / Steering (Curves) Yaw Stiffness Wheelbase too long Switches & Crossings Wheel Profile Set Wrong Back to Back Spacing Wheel Unloading Torsional Stiffness Unbalanced Load Dynamic Loading Traction & Braking Wheel Failure Dynamic Instability Mitigation Rubber mounted axles allow limited yaw, calculations demonstrate adequate flange clearance, calculations show worst case remains well within Nadal's Limit Wheelbase minimised through design optimisation As per Technical Specification Operational issue Back to back spacing within limits as specified in Technical Specification and Q&A responses (Number 9) Calculations demonstrate worst case wheel off-loading of 17%, i.e. well within Technical Specification, to be verified by lab test Designed for equal wheel loading, to be verified by lab test Low operational speed and advanced primary air suspension with integral adjustable damping Low centre of gravity and all axles braked & powered Wheelsets proved in mainline service on four wheel track inspection trolleys rated at 2000kg -11:1-

39 Appendix C: Safety Analysis And Risk Mitigations Speed Aerodynamics Coupling Dynamics Low speed operation Low speed operation Coupler designed according to Technical Specification and is well proven in service at Stapleford Miniature Railway Overturn Sway Speed Wind Centre of Gravity External Forces (Lateral) Debris Mechanical Failure Wheel/Axle Component Falls onto Track Suspension Failure Frame Speed Control System Failure Brake Failure Excessive Tow Speed Driver Error Low speed operation and low centre of gravity Low speed operation and emergency brake in case of overspeeding Low centre of gravity and limited cross sectional area Low by design - heaviest components are as close to rail level as possible Vehicle weighs approximately 300kg - substantial lateral load required Frame extends beyond tip of wheelsets Wheelsets designed specifically for gauge miniature train operation. Wheel sets are rated for use above mass of loco and are well within accepted limits, axles refitted, oversized high strength steel. Steel Base plate and second deck support plates prevent components falling, siding pieces prevent sideways movement of components, heavy grade strapping constrains shake loose of battery and hydrogen tanks. Rigid uprights and frame give multiple points to affix steel and plastic coverings. In the event of a heavy jarring event, components are isolated in their specific deck by coverings and plating. Suspension is intended for extended use in harsh operating conditions and both static and dynamic loads significantly lower than intended application Suspension system has been lightened to give a less stiff ride. Industrial use aluminium frame is light but provides a structure that is capable of withstanding forces well in excess of intended use. Initial design phase concentrated on loss of driver control resulting in controlled braking and shutdown of locomotive into safe mode. Emergency brakes proven in mainline service on four wheel track inspection trolleys rated at 2000kg, dual redundant braking system Designed to be safe at towing speeds in excess of Technical Specification Simple control interface, clear emergency stop function. -11:2-

40 Appendix C: Safety Analysis And Risk Mitigations Grounding Out Collision Hitting Something Driver Error Signalling Error Visibility Track Hazard Mechanical Failure Speed Control Being Hit Fire Lightning/External Component Failure Short Circuit Hydrogen Leak Battery Leak Base plate is well above stated clearance height Driver is fully practiced and used to the locomotive. Control system designed by driver. Driver in control of braking and rate of speed, in the event of loss of control locomotive will brake quickly and shutdown. Low operational speed and high braking rate allows for journey correction, or stopping in the event of a signal error. Low overall vehicle height, low operational speed allows line of sight operation Low operational speed allows line of sight operation, high braking rate Dual redundant braking system and high braking rate that exceeds minimum requirements of Technical Specification Limited top speed. Flexible software design allows for onsite reprogramming of speed limits. Clear user interface to allow graded speed operation. High visibility warning colouring. Rugged constriction. Hydrogen deck has numerous securing straps and forward and rear plates to prevent linear movement of tanks in the event of a collision. Earth bonding to both axles, all components electrically attached to frame Earth bonding to both axles, covers over high voltage components, appropriate fuse protection on all circuits, battery isolators & emergency isolation on traction circuit, Super capacitors mounted away from hydrogen to prevent ignition risk in the event of a capacitor failure. Supercapacitors tested with high voltage over a long period to assess warming risk, able to be handled after use, little or no heat risk from supercapacitors Hydrogen is able to ventilate in the event of a leak, while in use airflow is provided to prevent gas build up. Industry standard BOC gas tanks, inherently safe designed for transportation. Pressure regulation system over specified able to regulate gas pressure in excess of operational pressure. Hydrogen fire has low radiant heat, proximity burn risk reduced. Commercial batteries with long-life intended use. Routinely checked for leaks, and -11:3-

41 Appendix C: Safety Analysis And Risk Mitigations Mechanical Breakdown Solar Overheating Projectile/Explosion Battery Short Circuit Overcharge Electrical Failure Regenerative Braking Hydrogen Leak In Enclosed Space + Ignition Mechanical Failure Failure of Drivetrain Excess Torque Excess Speed Air Suspension inspected before use on a weekly basis. Low speed operation, high braking rate, automatic shutdown. Jockey wheels can be added to move the loco from the rails in the event of breakdown where the locomotive might not be able to be towed or continue to operate. Weather conditions unlikely to be problematic, clear panels to be flat Heat detection of critical components, allowing operation shutdown, hydrogen, batteries and supercapacitors can be monitored independently. Terminal covers to be placed on batteries, appropriate fusing to be placed inline with circuit. Battery isolator to be used Current limits on motor controller, state of charge monitoring on batteries, workflow put in place to dictate batteries stay charged. Diode and relay system allows supercapacitor charge during braking eliminating any risk to the battery during braking. Optionally the battery can take the regenerated load, in this case current monitoring regulated the current the battery receives preventing damage. High level of ventilation prevents gas accumulation, tanks are BOC standard 200bar tanks, proven history of safe use, energy equivalent to around only four litres of diesel, commercial fuel cell and piping, over specified connectors, isolation between high voltage / high current equipment and hydrogen components. Fuel cell has automatic selfpurge and shutdown. Drivetrain components proven in mainline service on four wheel track inspection trolleys rated at 2000kg Control system restricts speed to 15kph and components designed for much more arduous duty cycle. Suspension is intended for extended use in harsh operating conditions and both static and dynamic loads significantly lower than intended application. Suspension can be altered on site to improve ride quality. -11:4-

42 Appendix C: Safety Analysis And Risk Mitigations Supercapacitors Spark Capacitor explosion Electrocution Contact with High Voltage Contact with Unshielded Components (48V by design) Shielding Failure Earth Fault Chassis/Component Shorting Water Mechanical Failure Debris Component Failure Wrong side Failure of 3rd party components Failure of bespoke components. Electrocution low risk of injury due to low voltage across individual supercapacitors. Ignite hydrogen Supercapacitors installed at the front of the locomotive, shielded and isolated from hydrogen and possible hydrogen build up. Build up easily ventilated due to design of locomotive. Capacitor bank isolated and shielded. Located at opposite end of the locomotive to the gas valves. Insulated cables and connectors to be used; External (waterproof) covers on chassis whilst powered, all 48V circuitry to be enclosed in chassis. During operation batteries and supercapacitors are isolated from contact by plastic sheeting. Only members with electrical component experience handle electrical systems. Warning signs indicate hazards. All components / wiring carrying less than specified maximum current and are contained within covered frame Earth bonding across all metalwork on chassis and drivetrain. Locomotive is waterproofed and had been tested in moderate rain and snow conditions. Proven and certified 3rd party components used throughout; yearly electrical inspection Rewiring of systems resulted in the removal of redundant wiring. Components isolated in boxes to reduce debris. During testing locomotive is routinely inspected for debris. Components are removed during workshop modification, allowing internal access and removal or debris. Proven and certified 3rd party components used throughout; yearly electrical inspection Control system uses proved 3 rd party components, design is not off the shelf. In the event of control system failure, direct motor control can be achieved via laptop to motor parallel connection. Emergency stop and shutdown will initiate in the event of a control system failure during operation. Contact Injuries -11:5-

43 Appendix C: Safety Analysis And Risk Mitigations Drivetrain Contact Fixtures Running Somebody Over Heat Batteries Fuel Cell Motor Controller Motor Bearings Brakes Drivetrain Isolated from contact in the lower deck. Contact with wheel wheels and forward and rear wheels is possible, during nonoperation locomotive remains in standby mode with brakes engaged, all rotating parts are clearly marked. Majority of components are enclosed and sharp edges removed from other external component, frame edges have plastic caps to prevent cut injures. High braking rate and line of sight operation at low operating speeds. Contained in covered lower deck and isolated when in operation Contained within cover Covered by plastic siding Contained in covered lower deck and isolated when in operation Contained on underside of frame and within isolated lower deck Contained in covered lower deck and isolated when in operation, safety lever accessible from rear Supercapacitors Sharp Edges Chemical Injuries Batteries Couplers Squashed Between Vehicles Inhalation Batteries Hydrogen Heating test able to be handled directly after prolonged used in excess of intended operation. Mounting provides ventilation to supercapacitor bank. Majority of components are enclosed and sharp edges removed from other external component Majority of components are enclosed and sharp edges removed from other external component Contained within covered vehicle frame, batteries designed for heavy duty domestic use Designed in accordance with Technical Specification Battery compartment is well ventilated Hydrogen contained in standard 200bar BOC containers. Use within BOC guidelines. Inhalation hazard present with a build-up of hydrogen following a leak. Leak protocol requires the use of a hydrogen sniffer and soap test. Hydrogen build-up prevented by locomotive ventilation, inhalation risk extremely low during outdoor operation. Sniffer -11:6-

44 Appendix C: Safety Analysis And Risk Mitigations Poor Ride Excessive Forces Excessive/Sudden Braking Jerky Acceleration Software Failure Drivetrain Failure Suspension Failure use after overnight storage storage should be in an area with adequate ventilation, and a significant distance between locomotive and individuals. Sudden braking will only occur during an emergency stop. Control system designed to apply a rapid but controlled graded braking rate. Direct motor control using roboteq controller via laptop connection can be used as an alternative to the control system software in the event of a failure. Drivetrain components proven in mainline service on four wheel track inspection trolleys rated at 2000kg Locomotive not intended to carry passengers and limited effect on trailing load. -11:7-

45 Appendix C: Safety Analysis And Risk Mitigations IMechE Railway Challenge: Bottom-Up Safety Analysis and Mitigations Author: Peter Fisher, Syed Kamil Hashmi, Robert Ellis Issue Date: 14th of June 2013 Drivetrain Risk Malfunction Projectile Derailment Ride Injuries Heat/Fire Contact Injuries Unguarded Components Motors Unguarded Children or Unaware Persons Wheels Malfunction Heat/Fire Electrocution Excess Current Battery Explosion Mechanical Failure Projectile Mitigation Mechanical assemblies within covered frame and drivetrain well proven in service for 2000kg loading, low speed operation. Drive chain isolated with sidings base plate and plastic cover, in the event of failure parts will be held within the frame. Drivetrain components well proven in service for 2000kg loading, low speed operation. New wheelsets designed for miniature rail use, gravel and track debris contact wide of the track is removed driver experience noted identify track areas with difficult handling where lower speeds are to be used. Locomotive is not intended for passengers and limited effect on trailing load Low speed operation means this is highly unlikely Most of the mechanical components are within covered frame or difficult to get close to during normal operation Low speed operation with high rate emergency brakes and line of sight operation, most components are within covered frame, warning indicators Wheels are within the length of the frame, well inboard and protected as far as possible by the radial arms Temperature sensors shut system down in the event of a motor fault this will also apply a locomotive shutdown. Motor mounted on steel plate within metal frame, earthed to axles and within enclosed vehicle panels Control electronics continuously monitor charging currents. Supercapacitors to be used during regenerating eliminating current return to the batteries. Alternative battery regeneration option has current control via control system. Motors contained within covered frame -11:8-

46 Appendix C: Safety Analysis And Risk Mitigations Motor Jam Ride Injuries Wheel rail adhesion limits the deceleration rate A locked wheelset should not cause derailment (as per Derailment mainline operation) Contact Injuries Motor mounted on steel plate within metal frame within Heat enclosed vehicle panels. During operation it is not possible to access motors. Movement Motor mounted within enclosed vehicle panels Control Electronics Malfunction Battery Overcharge Explosion/Heat Traction Problems Loss of Brakes Derailment/ Collision Excess Braking Ride Injuries Jerky Acceleration Ride Injuries Excess Speed Derailment Incoherent Motor Control Ride Injuries Derailment Loss of Control Traction Issues High Voltage Failure Terminal covers to be placed on batteries, appropriate fusing to be placed inline with circuit. Battery isolator to be used. Batteries not used in regeneration, overcharge during braking no longer a risk If alternative regeneration is to be demonstrated i.e. using batteries, current sensors and motor controller regulate this. Mechanical brakes fail safe. Micro switches on E brake hold-off prevent loco operation in 'tow' mode. 2 sets of brakes increase redundancy Emergency brakes chosen such that deceleration rate is not severe. Control system braking graduated using software to provide a comfortable braking rate Software provides good graded acceleration rate providing a comfortable ride. Software limits maximum speed, driver has speed control. Emergency brake will be engaged in the event of software or control system failure. Raspberry Pi monitors commands to and from the motor control and tacho meter. In the event of problematic motor control the locomotive will be brought to a controlled stop and enter standby. Motor commands and acknowledgements are monitored; interface designed to reduce risk of incoherence between motors Control system designed to be fail safe; 'keep alive' systems used on many interfaces, emergency stop controls readily accessible -11:9-

47 Appendix C: Safety Analysis And Risk Mitigations Electrocution Fire Physical Electrocution Earthing & fusing provides route to ground and safety for erroneous chassis voltages; regular electronic safety tests undertaken Earthing & fusing provides route to ground and safety for erroneous chassis voltages; regular electronic safety tests undertaken All +48V wiring to be covered/insulated using insulated cabling & heat shrink. Entire chassis to be enclosed in waterproof/insulating cover -11:10-

48 Appendix C: Safety Analysis And Risk Mitigations Batteries Manual Handling Sprains & Strains Short Circuit Excess Heat Explosion Overload/Overcharge Explosion Chemical Injuries Heat Injury Leak Chemical Injuries Fuel Cell Vapour/Steam Exhaust Burn Leak/Accumulation of Hydrogen Explosion Electrical Failure Leak Hydrogen Fire / explosion Loco design allows easy removal of batteries; staff trained in manual handling for heavy batteries Insulated/protected battery terminals; appropriate fuse protection in line with batteries; battery isolator switch in line Insulated/protected battery terminals; appropriate fuse protection in line with batteries; battery isolator switch in line Current limits on motor controller; software monitoring of current flow; workflow to require that low state of charge batteries are not used Battery choice mitigates (batteries are sealed with vents for this scenario). Batteries enclosed within frame Current limits on motor controller; software monitoring of current flow; workflow to require that low state of charge batteries are not used. Overcharge during regeneration is eliminated when using Supercapacitor bank. Contained within covered vehicle frame, batteries designed for heavy duty domestic use. Batteries checked for leaks on a weekly basis, before testing and during workshop modification. Vapour is only warm, not hot enough to burn, exhaust to be kept way from electric / electronic components High level of ventilation prevents gas accumulation, commercial fuel cell and piping, over specified connectors, hydrogen leak detector fitted Fuel cell MCB protects fuel cell and circuit; additional downstream fuses on traction circuit further protect. Current monitoring engage emergency stop in fault scenario Tank is standard BOC 200 bar. During operation pressure regulator reduced pressure, operational pressure level is low. level of ventilation which prevents gas accumulation. BOC tanks have widespread use and are recognised as being safe if BOC standards are adhered to. Tanks are not required to be kept at certain temperatures but will -11:11-

49 Appendix C: Safety Analysis And Risk Mitigations not be exposed to unnecessary high temperatures. 2 nd deck installation prevents direct sunlight heating. Chemical Respiratory Fire / explosion Water Short Circuit Projectile (in accident) Electrical System Contact with High Voltage Electrocution Short Circuit / Over current Heat/Fire Contact Injuries Fumes/Inhalation Electrocution Fuse Blows Projectile Heat/Fire Earth Fault Electrocution Arcing Heat/Fire Physical Sharps Contact Injuries Operation only in outdoor or well-ventilated area, design is well ventilated to prevent gas build up. After use hydrogen to be stored in gas lock up away from individuals preventing accidental inhalation. Tank is low pressure, tank is inherently safe, metal hydride is stored in stainless steel tubes in a water bath inside a stainless steel enclosure Water contained in heavy duty stainless steel enclosure, panel and drainage system separating tank from electrical components below Mechanically secured with 2 x straps with 500kg braking load All +48V wiring to be covered/insulated using insulated cabling & heat shrink. Entire chassis to be enclosed in waterproof/insulating cover. Fusing reduces risk of short circuit/over current, as well as current monitoring. All components enclosed within frame and temperature monitored Safety procedure in event of fire requires users to retreat to safe distance Fusing reduces risk of short circuit/over current, as well as current monitoring. All components enclosed within frame and temperature monitored Fuses enclosed within appropriate holders Fuses enclosed within appropriate holders All metallic chassis elements common earthed; all component casings earthed. All arcing components enclosed within casings; all components enclosed in frame during operation. Unexpected shorts protected by fuses All cables to be terminated appropriately (terminal blocks, crimps, solder); all components to be inspected for sharp edges -11:12-

50 Appendix C: Safety Analysis And Risk Mitigations Entanglement Contact Injuries Suffocation Interference with Mechanical Projectiles Derailment Fire Sparks Fire Risk Hydrogen Pipe work Leak Explosion High Pressure Projectile Hose Out of Gauge Derailment Contact Injury Whipping Contact Injury Interference with Chassis Chassis & Suspension Malfunction Projectiles Derailment Wiring to be kept neat throughout vehicle; appropriate cable management techniques employed to mitigate risk Wiring to be kept neat throughout vehicle; appropriate cable management techniques employed to mitigate risk Wiring to be kept neat throughout vehicle; appropriate cable management techniques employed to mitigate risk Wiring to be kept neat throughout vehicle; appropriate cable management techniques employed to mitigate risk Wiring to be kept neat throughout vehicle; appropriate cable management techniques employed to mitigate risk Sparking components enclosed within appropriate casings; sparking components to be kept apart & underneath all hydrogen pipe work and equipment Over specified high pressure pipe work used throughout and installed by competent and experienced person Low pressure system which uses over specified high pressure pipe work used throughout and installed by competent and experienced person All hoses contained and secured within panels of vehicle frame All hoses contained and secured within panels of vehicle frame All hoses contained and secured within panels of vehicle frame and installed by competent and experienced person All hoses contained and secured within panels of vehicle frame separated from mechanical drive components Suspension is intended for extended use in harsh operating conditions and both static and dynamic loads significantly lower than intended application Failure of the air suspension is unlikely to cause the locomotive to derail; air suspension pressure -11:13-

51 Appendix C: Safety Analysis And Risk Mitigations to be checked prior to operation on a daily basis Out of Gauge Contact Injuries Derailment Sharp Edges Contact Injuries Poor Design Breakaway Derailment Track Twist Derailment Ergonomics Strains / Minor Injury Coupling Injury Toppling Contact Injuries Brakes Excess Speed Derailment Ride Injuries Excess Current Batteries Explosion Fire Chemical Injuries Excess Heat Fire Contact Injuries Excess Braking Failure of the air suspension will not cause the locomotive to go out of gauge Pressure in air suspension to be checked prior to operation on a daily basis - catastrophic failure is highly unlikely All exposed edges rounded off Numerous design calculations and laboratory tests Low operational speed, limited trailing load and limited gradient, driver located in trailing load Twist tolerance well within Technical Specification Locomotive not intended to carry passengers and should not require manual intervention during normal operation Operational risk, brakes automatically applied when loco not powered up, emergency button should always be operated prior to coupling Low centre of gravity, loco weighs 300kg and unlikely to topple over, limited speed Dual redundant fail safe braking system Operational speed limited to 10 kph by control system Continuous monitoring of batteries and their charging, contained within covered frame Continuous monitoring of batteries and their charging, contained within covered frame Continuous monitoring of batteries and their charging, contained within covered frame, commercial batteries intended for his sort of applications Emergency brakes well ventilated and mounted directly to heavy metal braked attached to steel base plate and metal frame Motors and emergency brakes within covered part of locomotive -11:14-

52 Appendix C: Safety Analysis And Risk Mitigations Ride Injuries Braking rate ultimately limited by wheel / rail adhesion -11:15-

53 Appendix D: Design Calculations Mechanical 12 Appendix D: Design Calculations 12.1 Concept Design Calculations Mechanical Calculations for IMechE Railway Challenge Authors: S Kent, A Hoffrichter, D Coombe, M Baslington Issue Date: 22 April 2012 edited by S Kent * from technical spec BASIC configuration TOTAL energy storage required number of motors 2 trailing load for energy challenge* 400 kg number of driven wheelsets 2 time* 3 hrs speed* 5 km/h TOTAL loco mass prediction distance 15 km batteries 60 kg gradient* 0.05 motors 20 kg ascent 0.75 km frame 50 kg ascent 750 m electronics 10 kg total mass 740 kg wheels & axles 40 kg total energy at the wheel 5E+06 Joules fuel cell 25 kg total energy at the wheel kwh tank 20 kg ballast 115 kg total 340 kg ** assuming no wheel slip * assuming Lynch Motor Company LEM * assuming Lynch Motor Company LEM Motor Torque Calculation MAX speed maximum current 75 A max voltage 36 V no load current* 6 A speed constant 138 rpm/v torque constant* Nm/A max rotation speed of motor* 4968 rpm torque Nm max rotation speed of wheelset 540 rpm wheel circumference m MAX Acceleration max linear speed m/min torque from each motor* Nm max linear speed m/s number of motors per wheelset 1 max linear speed kph gearing ratio 9.2 efficiency of chain / belt drive 95% ADHESION Calculation torque on each wheelset Nm total driving force N radius of wheelset 0.1 m vertical load 3335 N force at wheel rail interface per wheelset N requried coeff of friction total driving force N likely available wheel / rail adhesion 0.23 trailing load for traction challenge 600 kg wheel spin likely? No total load 940 kg max acceleration** 0.81 m/s/s -12:1-

54 Appendix D: Design Calculations Motor and Battery Motor and Battery Calculations for IMechE Railway Challenge Authors: P Fisher Authorised Editors: J Tutcher & P Fisher Issue Date: 22 April 2012 edited by S Kent * assuming Lynch Motor Company LEM TOTAL Battery Capacity VOLTAGE at Towing Speed battery voltage 12 V max linear tow speed 15 km/h battery capacity 90 Ah max linear tow speed m/s number of batteries 4 wheel circumference m energy capacity 4320 Wh max rotation speed rev/s energy capacity 4.32 kwh max rotation speed rpm gear ratio 9.2 max rotation speed of motor 3662 rpm motor speed constant* 138 rpm/v volts per rpm V/rpm voltage on motor at tow speed V MAX Regen Voltage at Running Speed MAX linear drive speed voltage from motor 10 km/h V Hydrogen Hydrogen Fuel Cell Calculations for IMechE Railway Challenge Authors: P Fisher Authorised Editors: P Fisher, J Tutcher & A Hoffrichter Issue Date: 22 April 2012 edited by S Kent * assuming Lynch Motor Company LEM FUEL cell size Hydrogen Storage Calculations control system efficiency 90% total energy required from fuel cell kwh battery conversion efficiency 75% hydrogen volume per kwh as per HFC manufacturer 625 l/kwh motor efficiency* 80% volume required std conditions 1750 l overall efficiency 54% density of Hydrogen 0.09 g/l total energy required at wheel kwh weight of Hydrogen g total energy required from fuel cell kwh time over which energy is required 3 hrs kwh of stored hydrogen rating of fuel cell kw maximum hydrogen storage in tank (mass) 500 g maximum hydrogen storage in tank (volume) 5563 l Energy avaliable from fuel cell with full tank kwh this would allow 18 h of operation on the gradient with trailing load -12:2-

55 Appendix D: Design Calculations IMechE Railway Challenge - Wheel Unloading Calculations Author: S Kent Issue Date: 11 June Track Twist Calculations Parameters Formulae Assumptions Mass 300 kg Vertical load = m x g Assume symetrical loading left to right No cylinders 4 n/a Cylinder area = pi x (radius) 2 Assume symetrical loading front to rear Cylinder radius 0.02 m Force in cylinder = pressure x area Assume negligible hysterisis Cylinder stroke (zero sag) 0.05 m Pressure = Force / area Assume suspensions set up with 25% sag = 12.5mm Suspension sag 25% P1 x V1 = P2 x V2 Wheelbase 1.25 m P2 = (P1 x V1)/V2 Track twist per metre 24 mm Static Cylinder Pressure Calculations Cylinder Extension / Compression Estimate Unloading Calculations Vertical load 2943 N Twist over wheelbase 30 mm Initial cylinder lenght / height m Total cylinder area m2 Twist per end 15 mm Initial cylinder volume 5E-05 m3 Pressure 6E+05 pascal Extension / compression per cylinder 7.5 mm Pressure bar Extension / compression per cylinder mm Compressed cylinder length / height 0.03 m Pressure psi Compressed cylinder volume 4E-05 m3 P2 for compressed cylinder psi Extended cylinder length / height Extended cylinder volume P2 for extended cylinder m 6E-05 m psi Unloading ratio Unloading percentage 16.7% 12.3 Curving Performance Calculations IMechE Railway Challenge - Curving Calculations Author: S Kent Issue Date: 11 June 2012 Clearance Available Nominal clearance based on 244mm back to back Additional clearance due to 242mm back to back Gauge widening Gauge widening Total clearance available Parameters Min curve radius Wheelbase = chord length Versine = (chord length) 2 / 8 x curve radius Versine 4 mm 2 mm 0.25 inches 6.35 mm mm 20 m 1.25 m 0.01 m mm Clearance Requried for Wheel Angle of Attack See sketch -12:3-

56 Appendix D: Design Calculations 12.4 Flange Clearance Calculations 10mm 625mm CALCULATIONS: X X / 106 = 10 / 625 X = (106 x 10) / mm X = 1.7mm -12:4-

57 Appendix D: Design Calculations 12.5 Flange Climb Calculations IMechE Railway Challenge - Wheel Unloading Calculations Author: S Kent Issue Date: 11 June 2012 Formulae Lateral load / Vertical load = (tan theta - coeff friction) / (1 - coeff friction x tan theta) Lateral load = Vertical load x (tan theta - coeff friction) / (1 + coeff friction x tan theta) Lateral force = (mass * velocity 2 ) / radius Assumptions Assume a large angle of attack Assume worst case wheel rail friction Assume all lateral load borne by outside wheels Assume tightest radius curve taken at maximum tow speed Calculations Theta (flange angle) Theta (flange angle) Worst case coeff riction Vertical mass per wheel Vertical load per wheel Max lateral load per wheel Total mass Maximum velocity Maximum velocity Minimum radius Max predicted lateral load Max predicted lateral load per wheel 81 degrees radians 0.6 n/a 75 kg N 878 N 300 kg 15 kph m/s 20 m N N -12:5-

58 Appendix E: Construction Drawings 13 Appendix E: Construction Drawings (Appendix are taken from the 2012 entry, design elements used here are largely unchanged in the 2013 entry. Appendix shows the redesigned axel and wheelsets used in the 2013 entry. Original concept drawings were made by Hamed Rowshandel) Original Concept Frame = square section extruded aluminium, connectors with hinges ends used for radial arms Drive = chain drive direct to wheels via intermediate shaft and wheel mounted gear sprocket Brakes = 24V electrically operated disc brakes (shown in green) Coupler = attach to top frame (not shown) Suspension = 4 x rear shocks from full suspension mountain bike Batteries = sit in a well in between the cross members on the lower level of the frame -13:1-

59 Appendix E: Construction Drawings 13.2 Frame 1500 c Ratchet cargo strap Hydride tank Rubber Insert Title: Frame V7 Projection: First Angle Author: S Kent Issue Date: 11 June 2012 Material: Bosch Rexroth Aluminium Profiles ALL DIMENSIONS IN MILLIMETRES NOT TO SCALE -13:2-

60 Appendix E: Construction Drawings 13.3 Coupler c xx xx xx Title: Coupler V3 Projection: First Angle Author: S Kent Issue Date: 11 June 2012 Material: Aluminium or Steel ALL DIMENSIONS IN MILLIMETRES NOT TO SCALE -13:3-

61 Appendix E: Construction Drawings 13.4 Axle Ø26 (unmachined) Ø20 (machined) Rubber lined shaft Title: Axle V5 Projection: First Angle Author: S Kent Issue Date: 11 June 2012 Material: Steel Bar ALL DIMENSIONS IN MILLIMETRES NOT TO SCALE -13:4-

62 Appendix E: Construction Drawings 13.5 Lay Shaft Ø15 (unmachined) Ø12 (machined) Title: Lay Shaft V4 Projection: First Angle Author: S Kent Issue Date: 11 June 2012 Material: Steel Bar ALL DIMENSIONS IN MILLIMETRES NOT TO SCALE -13:5-

63 Appendix E: Construction Drawings 13.6 Lay Shaft Mount Title: Lay Shaft Mount V6 Projection: First Angle Author: S Kent Issue Date: 11 June 2012 Material: Aluminium or Steel Plate ALL DIMENSIONS IN MILLIMETRES NOT TO SCALE -13:6-

64 Appendix E: Construction Drawings 13.7 Motor Mount Battery Shaft is approximately 35mm length, 10mm of which has a flat on it to fit into the emergency brake. The rear cover is approximately 40mm deep, but can be cut down if need be. 30 Title: Motor Mount V2 Projection: First Angle Author: S Kent Issue Date: 11 June 2012 Material: Aluminium or Steel Plate ALL DIMENSIONS IN MILLIMETRES NOT TO SCALE -13:7-

65 Appendix E: Construction Drawings 13.8 Emergency Brake Mount Hole in Baseplate Title: Emergency Brake Mount V5 Projection: First Angle Author: S Kent Issue Date: 11 June 2012 Material: Steel or Aluminium Plate ALL DIMENSIONS IN MILLIMETRES NOT TO SCALE -13:8-

66 Appendix E: Construction Drawings 13.9 Wheelset and Suspension Position OVERALL LENGTH = 1500 WHEELBASE = Title: Wheelset& Suspension Position V1 Projection: First Angle Author: S Kent Issue Date: 11 June 2012 Material: Aluminium or Steel ALL DIMENSIONS IN MILLIMETRES NOT TO SCALE Wheelset and new axle design -13:9-

67 Appendix E: Construction Drawings Control system design Requirement number Requirement Replace the national instrument computer with a low cost device to ensure proper interfacing The interfacing between the laptop and the locomotive must be done over Wi-Fi. In cases of loss of communication between driver and the system the locomotive must be able to come to a halt. A real time processing unit, this might be embedded with the interfacing device. In case of different real time process a reliable interface between the different devices must be ensured The system must be able to interface with the motor controller using the serial interface. The system must be able to interact with existing tachometer installed previously A reliable wireless communication needs to be installed to interact with other systems. These wireless systems should not interfere with the Wi-Fi communication on board. The system must allow the locomotive to detect its location on track. Three different points A, B & C on the tack must be identified when locomotive passes through them. The locomotive must be capable of interacting with all the current sensors on the system. The data produced though the system should be monitored and logged. All different parameters such as speed, acceleration, current drawn, battery voltage etc. must be included in the logging system. The train must be able to indicate in the cases of emergency. Indicators must be placed on the locomotive to identify any threats of fire or power loss. The designed system must be able to store regenerated energy and indicate the amount of energy stored. The system -13:10- should also allow the system to run on the stored energy only. This requirement Mandatory Preference

68 Appendix E: Construction Drawings arises from the IMechE railway challenge. When running on the stored energy the locomotive must be able to indicate when it uses the stored energy which has been regenerated. The designed system must be easy to debug and in case of redesigning the system by other teams must be quick and easy. The emergency circuitry must be controlled through the traction control system and shouldn t by pass the control system in any case or so. When the train passes through the points it must be able to detect its direction of travel, Forward or Backward The train can be entirely automatic use any logic method to control its speed and acceleration through its run. -13:11-

69 Appendix F: Finite Element Analysis 14 Appendix F: Finite Element Analysis -14:1-