23 rd international railway safety conference managing human factors in hong kong through

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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 Model4 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

Classification of Human Factor Incidents

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Trends of Human Factors Incidents

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Risk Assessment by Risk Matrix

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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

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Human Factors Incidents

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Case 1: 21 January 2010, East Rail LineFailure of Data Transmission Network

Failure of Data Transmission Network at East Rail Line

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Failure of Data Transmission Network at East Rail Line

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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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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


With Courtesy of MTR Corporation Limited


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Case 3: 21 October 2010, Tsuen Wan Line Breakage of Overhead Line Contact Wire

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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


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

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Thank You

23 rd international railway safety conference managing human factors in hong kong through

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