1. railway system in hong kong 2 railway network of hk hr: 11 lines, 84 stations lr: 12 routes, 68...
TRANSCRIPT
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23rd International Railway Safety Conference
Managing Human Factors in Hong Kong througha Risk-based Approach
Presented by
Paul H.B. SENRailways BranchElectrical & Mechanical Services DepartmentGovernment of the Hong Kong SAR
Railway System in Hong Kong
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Railway Network of HK HR: 11 Lines, 84 Stations LR: 12 Routes, 68 Stops Total Route Length: 218km 5.1 Million pax / weekday
Oversight on Safe Railway Operations
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Investigation ofrailway incidents
Ensuring the adoption of appropriate safety practices by the railway corporations;
Assessing and approvingnew railways and major modifications
Assessing and following up the railway corporations' improvement measures
What is Human Factors?
“… the environmental, organisational, and job factors, and human and individual characteristics which influence behaviour at work in a way which can affect health and safety.”
(Health & Safety Executive, UK)
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Recommendation
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HF Analysis accordingly to Risk Rating
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Risk Assessment
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Risk-based Model
4 Phases
Classificationof Incidents
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Risk Rating
LikelihoodConsequence
Causation
Equipment FailureHuman FactorsExternal Factors
Deficiency
SkillRule
Knowledge
Remedies
Continuous Monitoring
Plan-Do-Check-Act
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OR1 Unacceptable and shall be eliminated
OR2 Undesirable and shall be reduced by practicable control measures
OR3 Tolerable but shall be further reduced if possible
OR4 Negligible
Risk Assessment by Risk Matrix
Analysis of High Overall Risk Incidents
Human Deficiency
SkillRule
Knowledge
Performance Shaping FactorsTask design, interface design, competence
management, procedures, person,
environment
HFAnalysis
Remedial Measures
• Assigning designated staff to closely monitor
audits and communicate with third-party expert
• Avoid peak hours audits
• Prohibit uploading of new software patches to
the online operating systems during traffic hours
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Case 1: 21 January 2010, East Rail LineFailure of Data Transmission Network
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EAL Train Captain Pressing Door By-Pass Button without OCC Authorisation
Case 2:8 January 2012East Rail LineTrain Doors Opened when Train Stopped Short of Platform Rear End
Case 2: 8 January 2012, East Rail LineTrain Captain Opened Doors of Train Stopping Short of Platform Rear End
What’s wrong?
• Train captain did not identify the train stopping position• There is a procedural bar for door opening
Inaccurate Stopping Position
OCC Authorisastion
• Emergency activation by pressing door by-pass switch needs OCC authorisation• Train captain did not seek OCC authorisation
Near Miss• Potential safety threat of passenger falling to track at height
MMI• Switch relocation• Reminder label
Procedure
• Reinforcing the correct procedure for operating door by-pass switch
Aid• Installing stopping mark at each platform end
Vigilance
• Identifying train stopping position
RK
DS
Improvement Measures
Case 2: 8 January 2012, East Rail LineTrain Captain Opened Doors of Train Stopping Short of Platform Rear End
With Courtesy of MTR Corporation Limited
Case 2: 8 January 2012, East Rail LineTrain Captain Opened Doors of Train Stopping Short of Platform Rear End
Case 3: 21 October 2010, Tsuen Wan LineBreakage of Overhead Line Contact Wire
Equipment Failure- Traction motor- Train-bourne circuit breaker
Human Errors- Communication between OCC and Train Captain- Mistake in reporting the pantograph status to the Traffic Controller
Consecutive electric short-circuit faults
Overhead line contact wire overheated and burnt out
Snowball EffectHuman Errors- Procedure of the recovery
of traction power by Power System Controller
- Repeated attempts to reclose the traction DC circuit breaker before asking the platform supervisor to check the pantograph status on site
Agreed Mitigation MeasuresInstall a visual indicator in the driving cab as an visual aid for the train captain to confirm the position of the pantographs
Review and revise the operation control procedure for closing traction supply circuit breakers to provide clear steps for operators to follow
Replace train-borne circuit breakers with new ones of higher current rupture capacity
Case 3: 21 October 2010, Tsuen Wan LineBreakage of Overhead Line Contact Wire
13JAN
2011East Rail LineBreakage of rail as a result of crack propagating from an insulated rail joint bolt hole.
Restricted Manual Mode Train Operation at 20 kph
Case 4: Rail Breakage Incidentsat East Rail Line and Tsuen Wan Line
10FEB
2011Tsuen Wan LineAluminothermic weld defect causing rail breakage
Restricted Manual Mode Train Operation at 20 kph
Case 4: Rail Breakage Incidentsat East Rail Line and Tsuen Wan Line
Track Maintenance
East Rail Line
Dating back from13 January 2011 …
• Track maintenance staff had temporarily applied a bolt of smaller diameter
• Stress concentration at
bolt and bolt hole
Tsuen Wan Line
Dating back from10 February 2011 …
• Visual inspection every 3 days• Track maintenance staff carried out NDT once every 2 weeks• Could not detect any crack
Case 4: Rail Breakage Incidents atEast Rail Line and Tsuen Wan Line (2011)
Case 4: Rail Breakage Incidents at East Rail Line and Tsuen Wan Line (2011)
RecommendationsAdoption of ISO 9712
• Independent examination certification of NDT personnel
Standards
Improvement Measures
RecommendationsAdoption of EN14730
• Site aluminothermic weld procedure• Qualification of welding personnel
Standards
ConclusionCoping with human factors incidents – a job for both regulator and operator
No recurrence of railway incident caused by the similar human errors
Identifying high-risk scenarios and deploy resources accordingly for necessary improvements
Targeted safeguard measures for reducing the HF risks to a level as low as reasonably practicable