MTR : Adopts Improvement Measures after Lessons Learnt from Kwun Tong Line Service Disruption on 5 August 2017

PR092/17

19 October 2017

The MTR Corporation submitted a report to the Government today (19 October 2017) upon the completion of the investigation into the Kwun Tong Line signalling failure incident which took place on 5 August 2017. The Executive Review Panel, which was set up by the Corporation to look into the incident, concluded that the incident was managed in a safe manner according to established procedures. During the incident, the Corporation had made its best efforts to continue to provide train service and minimise the impact on passengers despite inevitable train journey delays. The Panel also put forth recommendations for improvements after completing a thorough investigation into the cause of the signalling failure, the recovery process and customer information rendered during the incident. (See Appendix for findings of the report)

The Corporation takes the service disruption on Kwun Tong Line on 5 August very seriously and set up an Executive Review Panel on 7 August to look into the incident. The panel was chaired by Managing Director Dr Jacob Kam with other five senior members from the Corporation. An expert group with four independent external experts was also appointed to provide professional advice to the panel.

The Panel concluded that the signalling fault resulted from intermittent data loss which was due to corrosion of electrical contacts in a junction box along one of the two concurrent copper datalinks on track-side near Ngau Tau Kok Station. The corrosion was caused by water ingress through a cable entry point on the originally water-tight junction box, which eventually resulted in loss or corruption of data in Kwun Tong station interlocking area. As such, the inter locking system executed the fail-safe protocol causing all trains in the affected area to stop. Such an intermittent cable fault had never happened in the Kwun Tong Line interlocking system in the past.

Safety, which is always MTR Corporation's top priority, was maintained throughout the incident. Instead of suspending the train service to identify the root cause by checking and testing all relevant equipment, the Corporation endeavoured to maintain service to minimise the impact on passengers while working on recovery at the same time. Throughout the incident, the recovery team worked very carefully to ensure the safety of trains while proceeding with the recovery work, and that resulted in the actual total recovery time required.

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The Panel agreed with the operational principle of maintaining train service as much as possible during incidents to minimise impacts on passengers and reduce the burden on other transport modes and on road traffic, when compared to the alternative of shutting down a section of a rail line. In fact, a steady train service on the Kwun Tong Line was maintained at a frequency of four to five minute intervals from around 2:30 pm until complete resumption in the evening, which was generally able to meet passenger demand.

To reduce the risk of recurrence of any similar signalling failure incident, alongside a number of other technical recommendations, the Panel suggested to convert the concerned signal interlocking long-distance copper datalink system in Kwun Tong station interlocking area into an fibre optic system to further enhance its fault tolerance. This work has commenced and the conversion will be completed by the end of October 2017.

The Corporation is also following up on other recommendations by the Panel, including:

• To enhance passenger communications and dissemination of information during atypical situations like this incident to enable customers to better understand the changing train service patterns, including the limited service in the initial stage of an incident.

• To enhance regular maintenance of data cables including checking data integrity to ensure smooth transmission.

"While the Panel has concluded that the incident handling was in accordance with the established protocol and the network operations were safe and orderly, the MTR Corporation is committed to taking the suggested improvement actions set out in the review report in line with our continuous improvement culture," said Dr Jacob Kam. "Once again, we apologise for the inconvenience caused to passengers who were affected by the incident on 5 August."

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About MTR Corporation

MTR Corporation is regarded as one of the world's leading railway operators for safety, reliability, customer service and cost efficiency. In its home base of Hong Kong, the Corporation operates ten commuter railway lines, a Light Rail network and a high-speed Airport Express link on which about 5.6 million passenger trips are made on a normal week day. Another 5.6 million passenger trips are made on the rail services it operates outside Hong Kong in the Mainland of China, the United Kingdom, Sweden and Australia. In addition, the Corporation is involved in a range of railway construction projects as well as railway consultancy and contracting services around the world. Leveraging on its railway expertise, the Corporation is involved in the development of transit-related residential and commercial property projects, property management, shopping malls leasing and management, advertising media and telecommunication services.

For more information about MTR Corporation, please visit www.mtr.com.hk.

Appendix

1. Overview

2. The MTR principle of recovering an incident is, first to ensure safety throughout the process, then to continue train service as much as possible, and at the same time minimise delays. This principle was consistently applied in the recovery of the signaling incident on the Kwun Tong Line (KTL) on 5 August 2017.

3. On that day at 1102 hrs., signal control of Kwun Tong station (KWT) interlocking area was lost. All points in the area could not be controlled or secured at both Operations Control Centre (OCC) and station level. Manual securing of points and manual train movement at low speed were required inside the area.

4. Signalling system incidents can be complex, and the incident on that day was unusually difficult because it was caused by an intermittent cable fault. The fault created changing symptoms through time and made fast diagnosis almost impossible. Although temporary recovery actions of the train service were completed at 1159 hrs and a steady service was achieved by 1432 hrs, the recovery team pressed on with a process of elimination testing and eventually found the fault and resumed the full signaling system capability by 2134 hrs.

5. Throughout the incident, train service was always maintained for the rest of KTL between Whampoa station (WHA) and Choi Hung station (CHH). Train service between CHH and Tiu Keng Leng station (TIK) took some time to be built up after the securing of points. By around 1432 hrs., train service headway on the KTL had been resumed to a steady state with headway between 4 minutes to 5 minutes. This service generally met the passenger flow demand on that day.

6. KTL signaling system has been maintained to a good standard. The line has experienced a stable and even slightly improving trend of signaling incident rate, even though the equipment is scheduled to be replaced in 2020.

7. Nevertheless, lessons learnt from this incident will help MTR improve its performance further.

8. The Executive Review Panel

9. On 7 August 2017, the Corporation set up an Executive Review Panel with the following terms of reference:

10. To establish the facts and circumstances surrounding the incident and its immediate aftermath;

11. To identify the root cause(s) and other contributory factors leading to the incident;

12. To review the timeliness and effectiveness of the incident response and recovery processes including the initial actions taken at site and the adequacy of the relevant procedures, to identify areas for improvement;

13. To assess the timeliness and adequacy of the information provided to the public in relation to the incident and the arrangement of train service and shuttle bus services, to identify areas for enhancement; and

14. To review the signalling system of KTL if it is still fit-for- purpose to meet the needs of current operations in terms of functionality and failure trend.

15. The findings of the Review Panel are summarised as follows:

16. Train Service

17. The MTR principle of recovering an incident is, first to ensure safety throughout the process, then to continue train service as much as possible, and at the same time minimise delays. This principle was consistently applied in managing the train service on the incident day.

18. After the initial efforts of securing points on track and releasing trains which were stranded between stations, through-line service on KTL was enabled at around 1159 hrs.