Oral Reply by Minister for Transport Khaw Boon Wan to Parliamentary Question on North-South Line Resignalling(1)

Mr Dennis Tan Lip Fong asked the Minister for Transport 

a.     whether he can provide an update on the progress of the integration of the new signalling equipment for the North-South and East-West MRT Lines; 

b.     what is the specific timeline for the completion of the tests and checks required beyond the description of "a few months" indicated in LTA/SMRT's press release; and

c.     what are the lessons learnt from the train disruptions that have occurred during this integration that may assist to improve service recovery measures for similar future breakdowns.

Mr Pritam Singh asked the Minister for Transport 

a.     what arrangements are in place to facilitate the smooth implementation of the communications-based train control (CBTC) signalling system on the North-South and East-West MRT Lines; and

b.     what operational constraints, challenges and hazards have arisen from the concurrent usage of the CBTC signalling system between Pioneer and Tuas Link on the East-West Line and on the entire North-South Line with the older Westinghouse fixed-block signalling system on the remaining stations of the East-West Line.

Reply by Minister for Transport Khaw Boon Wan:

1.     Installing a new signalling system is a complex exercise. For the entire North-South and East-West Lines, re-signalling will entail the installation of new equipment in more than 95 kilometres of train tracks, 141 trains, 54 stations and 3 train depots. This involves thousands of individual radio devices, more than 1,600 kilometres of communication and control cables, and the end-to-end rewiring of 4 different train models to accommodate the new hardware. That, however, is still the relatively easier part of the project. 

2.     The more challenging part is to integrate the new signalling system to work properly with the other rail systems, whilst the North-South and East-West Lines remain operational. It is akin to implanting a new central nervous system to a living body, whilst ensuring that the other organs continue to function. The London Underground, which also undertook such a re-signalling project a few years ago, took almost a year for its new system to stabilise. They were the first to warn us of these challenges, and I had shared their painful experience in this House early in the year. This was despite them implementing more than a hundred partial line closures to facilitate installation and testing.

3.     For us, closing the North-South or East-West Line is not an option. These two lines account for more than two million rides daily. We need to continue to operate the legacy signalling system even as we install and test the new system. The Member alluded to the complexity of keeping both signalling systems operational. This is indeed the case. 

4.     SMRT, LTA and system supplier Thales have therefore taken a cautious and progressive approach to installing and testing the new signalling system. I have advised them earlier to not rush this project. We started with more than 1,300 tests conducted during non-service hours, running empty trains. It was useful: glitches were discovered and software patches were duly installed and re-tested. After we were satisfied with these tests, we embarked on testing under “live” conditions, with trains loaded with commuters. Even then, we started small, with off-peak testing during the last hour of service from March 28th, and full Sunday testing from April 16th. During full Sunday testing, we also ramped up the frequency of trains to mirror weekday conditions. New glitches were discovered and more software patches installed and re-tested.

5.     Again, only after we were fully satisfied with these second and third phases of testing did we embark on full-weekday testing from May 28th. Full-weekday testing is necessary to stress the system under typical peak hour conditions, when trains run at high frequencies with heavy commuter loads. But again, to be extra careful, we scheduled the start of testing to coincide with the June school holidays, when commuter traffic was lighter. We are now at the tail end of this phase of testing for the North-South Line. 

6.     Despite our best efforts, commuters have had to endure some service delays, as forewarned by the London Underground. Nevertheless, the implementation has been smoother than what we feared. The prolonged testing and progressive stressing of the system has generally paid off. While it has not eliminated delays, it has minimised them.  

7.     As for project timeline, we are currently focused on stabilising the North-South Line. We have seen promising results from the latest software installed on July 14th. We expect to complete testing for the North-South Line before December. Testing of the East-West Line will then commence, for completion next year. The software improvements and lessons learnt from the North-South Line will be carried over to the East-West Line.

8.     The new signalling system will be a significant upgrade from the legacy system used since 1987. Once stabilised, train services will be more reliable. We can increase the number of trains to be deployed on the network, leading to shorter waiting times for commuters. However, much work remains to be done. I seek the public's continued patience and support.