Research Brief. Feasibility study into raising and lowering pantographs while trains are in motion. T778 - July Overview. Aims.

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1 Research Brief Feasibility study into raising and lowering pantographs while trains are in motion Overview Currently, raising the pantograph on the move on the GB railway is not standard practice, being undertaken only under limited circumstances and at low speeds by some train operators. For dual electrified trains the pantograph raise/lower transition between DC and AC electrification is typically undertaken at a standstill. The practice of raising the pantograph while the train is in motion is, however, applied regularly on the continent, and at high speeds. This research was intended to identify any risks that occur while raising and lowering pantographs on the move in the context of GB railways. There are several potentially significant operating benefits to be gained from routinely applying such a practice. Aims Findings On behalf of the Future Electrification Group (FEG), which is a sub-group of the Vehicle/Train Energy System Interface Committee (V/TE SIC), this research aimed to establish the acceptability of pantograph raising and lowering on the GB railway. This would allow, in regular operation of electric hybrid trains to traverse discontinuities in contact wire, which could enable simplification and cost reduction of the OLE layout. Risks of Pantograph Raising/Lowering at Speed The research has shown that it is viable to lower pantographs at line speed and, while avoiding some identified criteria, to raise them at speeds of up to 80mph. This could lead to time savings, and it also enables discontinuous electrification to be considered; coasting with a lowered pantograph can allow restricted clearance features to be negotiated, and operating flexibility is increased by coasting past obstructions. The simulations showed that the worst case was raising the pantograph onto a registration point at 125mph, the maximum predicted peak forces generated being 560N. RSSB R&D Programme Block 2 Angel Square 1 Torrens Street London EC1V 1NY research@rssb.co.uk default.aspx 1

2 Feasibility study into raising and lowering pantographs while trains are in motion Additional simulations were carried out, including raising two and three pantographs simultaneously, and raising the pantograph onto a gradient. These simulations gave very similar results to the single pantograph on plain wire scenarios, there being no significant change to the forces generated. As a result of the high predicted forces, vertical impact tests were carried out to ascertain the force required to damage pantograph contact strips. These tests showed single-piece bonded carbon type collector strips (as fitted to the class 91 and 390) to have a typical vertical impact resistance of 1500N or better. Consideration of the initial contact force characteristic in relation to the contact wire uplift generated by normal running has concluded that excessive contact wire uplift will not occur at pantograph raising. A limited number of arc damaged bonded, rolled-in, and clipped carbons were tested, which had impact resistances between 965N and 1560N. However, because of the low number of samples tested, and consequential uncertainty of the minimum impact resistance of these types, a general speed restriction of 80mph is recommended; whilst raising the pantograph at speeds up to 125mph is acceptable for undamaged bonded carbons. An analysis of the potential risks of pantograph raising at speed identified the following key risks, and corresponding mitigations: Raising the pantograph at speed onto specific features such as neutral sections, section insulators, and cross contacts will produce higher forces with increased risk of carbon damage. This is mitigated by appropriate planning of 'pantograph raising zones'. Windy conditions can affect train/pantograph aerodynamics and cause movement to OLE wires, potentially leading to high contact forces and wire uplifts when raising pantographs at speed. This is mitigated by limiting speeds for raising and lowering pantographs in high wind conditions; further research would be required to support the removal of these limitations. Ice conditions can damage pantograph carriers potentially weakening them. Research will be required to establish appropriate restrictions. Possible deterioration of pantograph components (eg bearings, chains, and Automatic Drop Device (ADD) components) as a result of more frequent pantograph raise/ lower cycles. This will require that accelerated life 'type' 2 RSSB

3 tests be carried out to ascertain pantograph maintenance requirements when operated under such regimes. Deliverables Method This research produced the report Feasibility study into raising and lowering pantographs while trains are in motion'; this report outlines the methodology, findings, and recommendations for industry members. The report contributes knowledge to those considering future electrification options for the GB railway. The feasibility of raising and lowering pantographs while trains are in motion was evaluated by means of: Surveying other railways' experience where this practice is used, and instances where trials have been undertaken on GB Rail. Liaison with rail operators in the GB and overseas, who currently raise the pantograph in motion. Liaison with contact strip and pantograph manufacturers. Modelling the forces generated when the pantograph is raised onto the contact wire. Assessment of the risks of damaging either the contact strips or overhead line components. Identifying additional risks of damage to the pantograph mechanism and/or contact wire. The quantification of the effect on combined pantograph and OLE (contact) system reliability. Stakeholders Experience A questionnaire was submitted to GB and European train operators to ascertain railway industry experience of raising the pantograph at speed. The responses showed that, on GB rail infrastructure, pantographs have, on occasion, been raised at speeds of up to 100 mph; whereas train operators in Europe will do this at speeds of up to 225 mph. Next Steps This research and its findings have been reviewed and accepted by the FEG. This research has fully addressed the key risks associated with raising and lowering pantographs while the train is in motion. It has shown that the use of a bonded carbon design of carrier can be safely raised against plain OLE at speeds of up to 125mph (except in wind or ice conditions). RSSB 3

4 Feasibility study into raising and lowering pantographs while trains are in motion Table 1 - Pantograph raise speeds, by train operator Train operating company experience Train operators Train speed at which pan raised (mph) East coast (GB) 20 Northern Rail (GB) 20 Virgin Rail (GB) 60 Hitachi (GB) (while on test by manufacturer) 62 Mentor test train (GB) 100 Eurostar (Continental Europe and GB High Speed 1) 170 Amtrak (US) 60 DB (Germany) 185 SNCF (France) 225 This research project concluded that increased speed limits could be established for pantograph raising in high wind conditions; but further research and testing would be required to establish appropriate limits. Previously within Module AC, Rule 12.1 controlled lowering the pantograph on the move to avoid damage. Rule 16.4 allowed coasting at 20mph with lowered pantographs to pass an area of damaged infrastructure, then unless otherwise specified by train operating company instructions, to stop before raising the pantograph. The V/TE SIC has accepted that the results of this research indicate that there is no technical reason that pantographs cannot be lowered at line speed and can be raised at up to 80mph in planned operational circumstances. On behalf of the V/TE SIC, RSSB has agreed to progress the submission of a proposal for a Rule Book change for review and progression by the industry members of the Traffic Operation and Management Standards Committee. Since industry does not currently plan to raise pantographs at higher speeds (above 80mph), the FEG has agreed no further action is required to investigate the effect of raising at greater speeds. Accelerated pantograph life 'type' tests were also recommended, however the FEG concluded that further testing would not be 4 RSSB

5 required since existing maintenance regimes will be used to identify any emerging abnormalities. This research project concluded that speed limits should be established for pantograph raising in ice conditions. When introducing new designs of carrier strip or revised carbon grades with reduced metal impregnation, vertical impact testing should be carried out to confirm their suitability. Further testing will be required if plain carbon is used as part of the Energy TSI. These tests should be carried out by the carbon manufacturers. Tests conducted as part of this project have provided enough evidence to propose that no further testing is required for existing grades and the practical application will be done via compatibility assessments and in-service running. The research also noted that further simulation should be conducted for operation on other OLE types where the characteristics vary significantly from those of Mk IIIB OLE. This is limited to the heavy ex 1500V DC OLE previously installed on Manchester - Sheffield - Wath (MSW), Great Eastern (GE) and Shenfield - Chelmsford - Southend (SCS) electrifications, which represent 3-5% of the existing OLE network. This was accepted by the FEG, and RSSB has agreed that this will be incorporated into Guidance within Standards Project 09/013. Contact For more information please contact: Head of Engineering Research R&D Programme RSSB research@rssb.co.uk RSSB 5