Exploring the systematic causes of Beijing subway PSD accident

Transcription

1 Exploring the systematic causes of Beijing subway PSD accident Shijie Zhang, Ph.D. student State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University

2 Outline Background and Motivation Background Beijing subway The application of platform screen doors Overview of the accident Beijing subway PSD accident analysis with CAST Physical and Operational Level Management level Passenger s role as context & controller Changes & Conclusions

3 Outline Background and Motivation Background Beijing subway The application of platform screen doors Overview of the accident Beijing subway PSD accident analysis with CAST Physical and Operational Level Management level Passenger s role as context & controller Changes & Conclusions

4 Background The Beijing Subway is a rapid transit rail network that serves the urban and suburban districts of Beijing municipality. The network has 18 lines, 334 stations[a] and 554 km (344 mi) of track in operation. The subway is the world s busiest in annual ridership, with 3.41 billion trips delivered in 2014, averaging million per day, with peak single-day ridership reaching million. Beijing 2015 and "twelfth five-year" period for national economic and social development statistical bulletin. Beijing Municipal Statistics Bureau Retrieved

5 People fell off platform From House of cards S02 Beijing subway, 2016 Time line station consequence Jan.28, 2016 line 1 Yuquanlu one death Fab.14, 2016 line 2 Dongzhimen one death Fab.28, 2016 line 1 Yuquanlu one death Mar.2, 2016 line 1 Wanshoulu one death

6 The purpose The application of platform screen doors(psds) Safety: Train piston wind & Fall off platform Energy conservation: Air condition Prevent suicide The system become more complicated

7 The gap About 300mm in width Hazard: Train start with people between train doors and PSDs.

8 Historical accident 2.Could not get onboard because it s crowded 3.PSDs already closed 1.Run to the train when doors were closing Shanghai metro line 1, Nov.6, The man got killed by the departing train

9 Overview of the accident The location On November 6, 2014 at 18:57 Beijing subway line 5 Huixinxijie Nankou station Accident spot A woman fell out the train and got trapped between the train door and the PSD and train departed The women died in hospital at 20:20

10 Passenger volume at peak APEC Beijing subway has serious tidal phenomena. Huixinxijie Nankou Important interchange station

11 Outline Background and Motivation Background Beijing subway The application of platform screen doors Overview of the accident Beijing subway PSD accident analysis with CAST Physical and Operational Level Passenger s role as context & controller Management level Changes & Conclusions

12 Train & station system Technical system Human Signal system Driver Train door controller PSD controller Platform staff Train doors PSDs Passenger Hazard:Train start with people between train door and PSD. Safety constrain:there must be no person between train doors and PSDs when the train start.

13 Measures Driver s check Plate on PSD Emergency tools Handle on PSDs Platform staff s assist

14 Time 18:57 轨道交通控制与安全 Victim Train doors PSDs start to close fell out of train start to close got trapped closed closed got hurt sent to hospital 20:20 died in hospital The Proximate Events Driver forgot to check the gap started the train stopped the train Platform staff didn't find the emergency other passengers looked for staffs and emergency tools

15 Safety Control Structure Driver Human got stuck? Open/close train doors Depart the train, Open/close PSDs Condition of doors, starting signal Emergency break Platform Staff emergencey Passenger nearby Emergency break Emergency Condition of door area Signal system Open Enable Train door controller Condition of train doors Open/ close Condition of train doors Train doors GAP PSDs Open /close Condition of PSDs Condition of PSD Open/close PSD PSD controller Condition of door area

16 Physical Level No sensor in the gap. Driver Door control system Close the doors Signal system Role: Controller Safety responsibilities (requirements) Release break only if both train doors and PSDs are closed&locked. Closed & locked? Closed & locked Starting signal Close the doors Closed&locked? Condition between train door & PSD Deficiencies in system design: Safety constrain not allocated to a controller. Train door controller Role: Controller Safety responsibilities(requirement) Start to close the door specified time Stop door with residence over 150N alarm Unsafe Interaction PSD controller Role: Controller Safety responsibilities(requirement) Start to close the door specified time Stop door with residence over 150N Plate obstruct Train doors Gap PSDs PSDs closed, no equipment can detect gap. Sequence : Train doors close after PSDs. Passenger system Passengers getting on or getting off

17 Physical Level Driver Door control system Train door controller Role: Controller Safety responsibilities(requirement) Start to close the door specified time Stop door with residence over 150N Close the Signal system doors Role: Controller Safety responsibilities (requirements) Release break only if both train doors and PSDs are closed&locked. Closed & locked? Closed & locked Starting signal Close the doors Closed&locked? PSD controller Role: Controller Safety responsibilities(requirement) Start to close the door specified time Stop door with residence over 150N Condition between train door & PSD Deficiencies in system design: Assist: Drivers may neglect the check especially on rush hour with the assist of equipment. alarm Train doors Gap Plate obstruct PSDs Passenger system Passengers getting on or getting off

18 Condition of doors, starting signal 轨道交通控制与安全 Depart the train, Open/close train doors&psd Train door Driver Emergency break Driver Human got stuck? Platform Staff emergency Physical Controllers Passenger nearby the doors Emergency break PSD Passengers getting on or getting off Door area Operational level emergen cy Condition of door area Safety responsibilities Supervise passenger transfer, ensure safe starting conditions Unsafe control actions that occurred Start the train with a passenger trapped Contextual reasons for the behavior In rush hour, driver worked under the pressure of the busy timetable; Equipment provided unreliable assist. Mental model flaws that contributed to it The driver was too dependent on preventing equipment; Neglect the importance

19 Operational level Condition of doors, starting signal Depart the train, Open/close train doors&psd Train door Driver Emergency break Human got stuck? Platform Staff emergency Physical Controllers Passenger nearby the doors Emergency break PSD Passengers getting on or getting off Door area emergency Condition of door area Dysfunctional Interaction Passengers cannot found platform staffs to report the emergency Reason: The platform was crowd, vision was blocked and environment was noisy. Platform staffs find it hard to supervise all the doors. Passengers cannot reach emergency tools. Reason: No handy emergency break or emergency call device. Cannot get to tools nearby due to the crowds.

20 Emergency button Emergency button on platform Emergency button upon train doors Accident spot Only set on 2 middle doors of each carriage Car 1 C 2 C 3 C 4 C 5 C 6 Platform track Platform Platform track

21 Operational level Driver Human got stuck? Driver Human got stuck? Condition of doors, starting signal Depart the train, Open/close train doors&psd Emergency break Platform Staff emergency Physical Controllers Passenger nearby the doors Emergency break emergency Condition of door area Condition of doors, starting signal Depart the train, Open/close train doors&psd Emergency break Platform Staff Physical Controllers Passenger nearby the doors Condition of door area Train door PSD Passengers getting on or getting off Door area Door area Train door PSD Passengers getting on or getting off

22 Operational level Condition of doors, starting signal Depart the train, Open/close train doors&psd Train door Driver Emergency break Human got stuck? Platform Staff emergency Physical Controllers Passenger nearby the doors Emergency break PSD Passengers getting on or getting off Door area emergency Condition of door area Passengers nearby Safety responsibilities Report to platform staffs or the driver, or use the stop the starting. Unsafe control actions that occurred Start the train with a passenger trapped Contextual reasons for the behavior Crowded station & No handy tool Mental model flaws that contributed to it No enough knowledge to cope with this situation Not prepared so panicked Passengers are instable as volunteer controllers of door system

23 Passengers Driver Closed & locked Close the doors Starting signal Door control Signal system People system often been kidnapped Closed & locked? Close the by door Closed&locked? passenger flow It s hard to get onboard without push and squeeze. Train door controller PSD controller Passenger system alarm Train door PSD Pull open Passengers getting on or getting off Role:controller Safety responsibilities Stop getting onboard when the car is full Stop at the alarm. Unsafe control actions that occurred Be the last one to get on a packed car Did not obstruct the closing train doors Contextual reasons for the behavior It s hard to get onboard without push and squeeze. People often been kidnapped by passenger flow Hope to get home soon Mental model flaws that contributed to it People overlooked the importance of order at rush time Condition between train door & PSD Human-machine interaction Contextual reasons & Mental model Passengers mental model could be greatly influenced by passenger flow. Passengers as controllers of themselves

24 Passengers role Volunteer controllers of the door system the instable controller Controller of themselves when during transfer make advisable decision with crowds Context of interaction and of other controllers the crowds block interactions

25 Management level Coordination and Communication Driver Emergency Time table Platform staff work arrangement Management Municipal Government Traffic flow warning, station close order Passenger flow not been controlled effectively. Lack of regular and efficient approach to feedback when the station/individual are out of capacity. OCC Station feedback Traffic flow warningcondition of passenger flow Passenger flow control Passengers in station temporary traffic policy Passenger flow Control of station Suited context Evening peak Passengers in station Degree of crowdedness Difficulty for passenger transfer Interchange station Frequency of the trains Pressure of driver Station dwell time Tidal with passenger flow

26 Suggestions A specific physical controller should take this safety constrain in charge. And there should be a stable feedback to monitor the gap More propaganda should be carried out by public education and the operation corporation not only about behaving in order but coping with emergency. Subway operation cooperation should use tidal control strategy and control the passenger flow if it s beyond the capacity.

27 Outline Background and Motivation Background Beijing subway The application of platform screen doors Overview of the accident Beijing subway PSD accident analysis with CAST Physical and Operational Level Management level Passenger s role as context & controller Changes & Conclusions

28 Changes Longer & louder alarm Train doors and PSDs close at the same time

29 Changes Passenger limiting Volunteers at peak time Lookout stage

30 Conclusion A CAST analysis was made and gave us some systematic suggestions. Passengers should be thought from different roles within subway system. Control structure should be designed dynamically with different passenger flow.

31 Q&A! State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University