1. Managing Human Factors in Hong Kong through a Risk-based Approach
23rd International Railway Safety Conference
Managing Human Factors in Hong Kong through
a Risk-based Approach
Presented by
Paul H.B. SEN
Railways Branch
Electrical & Mechanical Services Department
Government of the Hong Kong SAR

2. Railway System in Hong Kong
Railway Network of HK
HR: 11 Lines, 84 Stations
LR: 12 Routes, 68 Stops
Total Route Length: 218km
5.1 Million pax / weekday
Railway System in Hong Kong
Relatively small railway network with a total track length of about 218 km
Hong Kong is a densely populated city
5.1 millions pax per weekday on the average (7.18 million population in HK as at mid 2013)
Rail transport is an indispensable part for Hong Kong people
Highly automated with minimum intervention
Human factors do play a vital part in rail operation
High public expectation for level of service

3. Oversight on Safe Railway Operations
Ensuring the adoption of appropriate safety practices by the railway corporations;
Investigation of
railway incidents
Assessing and following up the railway corporations' improvement measures
Assessing and approving
new railways and major modifications
Railway lines operated by the MTR Corporation Limited
RB of EMSD is the regulatory body of all railway lines
Empowerment of the Mass Transit Railway Ordinance in Hong Kong
Statutory role to oversee the safe operation of the railways
Main functions:
Investigating into railway incidents;
Ensuring the adoption of appropriate safety practices by the railway corporations;
Assessing and approving new railways and major modifications; and
Assessing and following up the railway corporations' improvement measures

4. 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)
Human beings are fallible: Human errors & violation
Someone not doing the right thing at the right time
Passenger behaviour: Publicity & education – a joint effort with operator
Focus on railway staff: contractors and MTR employees – Staff errors could be reduced (if not eliminated) by design and management

5. Continuous Monitoring
Risk-based Model
4 Phases 1 2 3 4
Classification
of Incidents
Risk Assessment
HF Analysis accordingly to Risk Rating
Recommendation
Causation
Equipment Failure
Human Factors
External Factors
Risk Rating
Likelihood
Consequence
Deficiency
Skill
Rule
Knowledge
Remedies
Continuous Monitoring
Plan-Do-Check-Act
Risk-based model involves:
Classifying incidents
Assessing the likelihood, consequence of any known hazards and determine the risk levels
Analysing the HF: human deficiency (SRK) and performance shaping factors
Recommendation for incident specific remedies

6. Classification of Human Factor Incidents
- Non-HF Related: Pure equipment failure & External Factors
- Focus: HF related: Staff behaviour & Passenger Behaviour
Human factors incident classified by type of errors
Classified incidents recorded in Incident Data Management System

7. Trends of Human Factors Incidents
Amongst the reportable incidents caused by staff behaviour, it is more common for the staff behaviour to have an impact on OSH
Except 2011: Measured by incident number, the impact on passenger / public safety overshot the OSH impact
Past 2 years: Raise the attention on any HF elements involved in incidents

8. Risk Assessment by Risk Matrix
Use a conventional risk matrix to determine the risk level
10 levels of likelihood of occurrences – Similar occurrences in the past
7 levels of consequence – Impact on public safety (measured by no. of fatalities) or service (duration of service disruption)
Results in 4 levels of overall risk

9. Risk Assessment by Risk Matrix
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

10. Analysis of High Overall Risk Incidents
Performance Shaping Factors
Human Deficiency
Task design, interface design, competence management, procedures, person, environment
Skill
Rule
Knowledge HF
Analysis
HF analysis – to identify shortfall and find out ways to make good
Use performance shaping factors as a guide to comprehend the cause of incidents due to deficiency of staff in respect of skill, rule and knowledge (SRK)
Best to be illustrated by HF incidents

11. Human Factors Incidents

12. Case 1: 21 January 2010, East Rail Line Failure of Data Transmission Network
An evening peak at the East Rail Operations Control Centre
For the traffic controller Seeing is believing – The railway is safe and seen to be so by
Tracking the locations of trains
Communicating with train captain with radio
Making public announcement

13. Failure of Data Transmission Network at East Rail Line
All these operations at the East Rail Line Operations Control Centre are supported a data transmission network
Fibre Distributed Data Interface (FDDI)

14. All of a sudden, all terminals became dumb,
The traffic controllers at the East Rail Line Operations Control Centre could not track the locations of trains
Radio communication with all train captains was also lost.
Train services on the whole line were suspended … all for safety
30,000 passengers were stranded during the incident
It takes an hour for recovery of train services

15. Photomontage of OCC ATS Blackout

16. Case 1: 21 January 2010, East Rail Line Failure of Data Transmission Network
Third-party supplier’s computer engineer was conducting a regular software audit to ensure the integrity of the data network
To do so, he executed an off-line software optimisation program.
He felt hungry and left for dinner!
The program he had loaded was a slip of hand, it went online, overloaded the data network with junk data, and paralysed the FDDI network
causing the failure.

17. Failure of Data Transmission Network at East Rail Line
All these operations at the East Rail Line Operations Control Centre are supported a data transmission network
Fibre Distributed Data Interface (FDDI)

18. Case 1: 21 January 2010, East Rail Line Failure of Data Transmission Network
Third-party supplier’s computer engineer was conducting a regular software audit to ensure the integrity of the data network
To do so, he executed an off-line software optimisation program.
He felt hungry and left for dinner!
The program he had loaded was a slip of hand, it went online, overloaded the data network with junk data, and paralysed the FDDI network
causing the failure.

19. Case 1: 21 January 2010, East Rail Line Failure of Data Transmission Network
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
Ensure that the online system would not be affected by implementing tighter working procedures
Establish policy of no software audits during peak hours and operating hours as far as possible
Use security device (interlocking switch) to bar any attempt to upload new software patches to the online operating systems during traffic hours

20. Train Doors Opened when Train Stopped Short of Platform Rear End
Case 2:
8 January 2012
East Rail Line
Train Doors Opened when Train Stopped Short of Platform Rear End
EAL Train Captain Pressing Door By-Pass Button without OCC Authorisation
On 8 January 2012, a portion of a passenger train stopped short of the platform stopping mark.

21. Inaccurate Stopping Position
Case 2: 8 January 2012, East Rail Line Train 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
It is not uncommon for trains to stop in an inaccurate position
The train doors will not be opened until the train captain has confirmed that the train is in the correct position.
A door by-pass switch was provided at the control console of the cab right in front of the train captain.
The original design intent was to allow evacuation in case of emergency.
Authorisation of the OCC was needed before a train captain can press the door by-pass button.
The train doors were opened as the train captain pressed the door by-pass switch without authorization of the OCC
That risked passengers riding on the last train compartment fall to track from a height of about 1.1m
Near Miss
Potential safety threat of passenger falling to
track at height

22. Case 2: 8 January 2012, East Rail Line Train Captain Opened Doors of Train Stopping Short of Platform Rear End
Reinforcing the
correct procedure for
operating door by-pass
switch
Identifying train stopping position K R
Vigilance
Procedure
Improvement Measures S D
Aid
MMI
Installing
stopping mark at
each platform
end
Switch relocation
Reminder label

23. Vertical stopping mark in Hung Hom Station

24. With Courtesy of MTR Corporation Limited
Case 2: 8 January 2012, East Rail Line Train Captain Opened Doors of Train Stopping Short of Platform Rear End
Follow-up Actions:
Refresher training programme developed to remind train captains to be vigilant in identifying the train stopping position
The training programme also reinforced the correct procedure for operating the door by-pass switch
Vertical stopping mark at platform end
We recognised that the environment and the design of man-machine interface were performance shaping factors for this incidents.
Half a year after the incidenb, the door by-pass switches were all relocated from the front to the back of the train captain to avoid inadvertent operation. Door bypass switch is now located at positions such that Train Captain has to stand-up and walk so as to activate the switch.
The switch relocation work was completed in Jul 2012.
Label was provided near door by-pass switches to further remind the train captain proper usage of the facility.
With Courtesy of MTR Corporation Limited

25. Case 3: 21 October 2010, Tsuen Wan Line Breakage of Overhead Line Contact Wire
In the morning of 21 October 2010,
- The overhead line in a section of the Tsuen Wan Line (between Prince Edward Station and Yau Ma Tei Station) was burnt out as a result of repeated short-circuit faults.
It took some time to figure out what happed and further 2.5 hours to re-connect the overhead line
Altogether, train service at Yau Ma Tei Station was suspended for 3 hours
100,000 passengers were affected

26. Case 3: 21 October 2010, Tsuen Wan Line Breakage of Overhead Line Contact Wire
Cause of Incident
Primarily originated from a simple equipment fault
But successive human errors are key contributory factors to the severe service impact

27. Case 3: 21 October 2010, Tsuen Wan Line Breakage 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 Effect
Human 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
Originated from a short-circuit fault inside the traction motor
Limitation of the train-bourne circuit breaker
train-borne circuit breaker damaged
Overhead line traction supply circuit breaker was tripped
Incident train captain was instructed to lower the pantograph to isolate the fault
He acted accordingly and the Power System Controller attempted to resume the traction power supply
In fact, the action of the Train Captain was futile.
The DC circuit breaker tripped again
Nobody checked the status of the pantograph on site
Power System Controller did not ask for better information about site situation
He repeatedly attempted to re-close one of the DC circuit breakers for that incident section
That resulted in 5 consecutive electric-short circuit faults
A fault of the traction motor alone would not have caused an incident as such. That was the outcome under a snowball effect and human errors are key contributory factors.

28. Agreed Mitigation Measures
Case 3: 21 October 2010, Tsuen Wan Line Breakage of Overhead Line Contact Wire
Agreed Mitigation Measures
Install a visual indicator in the driving cab as an visual aid for the train captain to confirm the position of the pantographs
Replace train-borne circuit breakers with new ones of higher current rupture capacity
Review and revise the operation control procedure for closing traction supply circuit breakers to provide clear steps for operators to follow
We figured out that we need to tackle two human factors issues.
First, the Train Captain did not correctly report the pantograph status to the Traffic Controller.
MTRCL agreed to install a visual indicator in the driving cab as an visual aid for the captain to confirm the position of the pantographs
Second, the Power System Controller attempted to reclose the traction supply circuit breakers for several times before asking the platform supervisor to check the pantograph status on site.
We reviewed the operation control procedure with MTRCL.
MTRCL then revised the procedure for closing traction supply circuit breakers to provide clear steps for operators to follow.

29. Restricted Manual Mode Train Operation at 20 kph
Case 4: Rail Breakage Incidents
at East Rail Line and Tsuen Wan Line
2011
Restricted Manual Mode Train Operation at 20 kph
East Rail Line
Breakage of rail as a result of crack propagating from an insulated rail joint bolt hole.
JAN 13
Two rail breakage incidents occurred in early 2011.
The first on the East Rail Line on 13 January 2011.
Train services were severely affected as trains needed to travel in “restricted manual mode” at 20 kph near the affected rail section.

30. Restricted Manual Mode Train Operation at 20 kph
Case 4: Rail Breakage Incidents
at East Rail Line and Tsuen Wan Line
2011
Restricted Manual Mode Train Operation at 20 kph
Tsuen Wan Line
Aluminothermic weld defect causing rail breakage
FEB 10
The secondt on the Tsuen Wan Line on 10 February 2011.

31. East Rail Line Tsuen Wan Line
Case 4: Rail Breakage Incidents at East Rail Line and Tsuen Wan Line (2011)
Track Maintenance
East Rail Line
Dating back from
13 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 from
10 February 2011 …
Visual inspection
every 3 days
Track maintenance
staff carried out NDT
once every 2 weeks
Could not detect any
crack
For the East Rail Line incident, the incident could have been avoided if a suitable size bolt was used in the first place.
The entire rail network was checked and 7 IRJs with a smaller bolt were identified and replace.

32. Case 4: Rail Breakage Incidents at East Rail Line and Tsuen Wan Line (2011)
Recommendations
Adoption of EN14730
Site aluminothermic
weld procedure
Qualification of
welding personnel
Standards
Improvement Measures
Recommendations
Adoption of ISO 9712
Independent
examination
certification of NDT
personnel
Standards
A consultant reviewed the rail inspection and maintenance regime.
He recommended
adopting the EN14730 standard to improve the site alumnothermic welding procedure
adopting the ISO9712 standard for independent examination and certification of NDT personnel

33. Conclusion
Coping 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
Effective management of railway incidents due to human error
- Number of human factor incidents has been substantially contained with a steadily declining trend
- No recurrence of railway incident caused by the similar human errors
Efficient utilization of resources
- Focus manpower resources more efficiently on our identified high-risk scenarios
- Devise very targeted safeguard measures and inspection programmes in order to reduce the risk arising from human factors to a level as low as reasonably practicable

34. Thank You