Oral Reply by Minister for Transport Chee Hong Tat to Parliamentary Questions on MRT Service Disruptions in February 2025

Mr Leong Mun Wai asked Minister for Transport 

a.     whether an update can be provided on the lessons learnt from the recent MRT service disruptions on the North-South Line on 7 February 2025, North-East Line on 10 February 2025 and Circle Line on 11 February 2025; and 

b.     what are the actions that the Ministry will take to prevent a repeat of similar breakdowns.

Mr Dennis Tan Lip Fong asked the Minister for Transport 

a.     whether any of the recent MRT disruptions leading to delays in MRT services on the North-South Line, North-East Line and Circle Line in February 2025 were caused by a maintenance issues; and 

b.     what steps will be taken to ensure that similar incidents can be minimised or avoided in future.

Reply by Minister for Transport Chee Hong Tat:

1     LTA is investigating the root causes of the three incidents on 7, 10 and 11 February. I will share the preliminary findings for each incident.

NSL incident on 7 Feb

2.     First, the North-South Line (NSL) incident on 7 February. At around 5.15 am, an engineering vehicle broke down at a railway crossing in Bishan Depot after routine maintenance works. This engineering vehicle comprises three wagons, which are used for carrying equipment and materials for maintenance works, and two locomotives, which are used for moving the wagons along the MRT tracks. As trains departing Bishan Depot for the mainline need to pass through this railway crossing, SMRT was unable to launch trains from Bishan Depot. To allow operations to resume, SMRT attempted to move the stalled engineering vehicle using a rescue train. When the rescue train started moving the stalled vehicle, SMRT discovered that some of the wheels of two of the wagons had come off the rails. 

3.     By the time the engineering vehicle stalled, only 3 out of 39 trains that were scheduled to serve the NSL that morning had been launched from Bishan Depot. 

4.     To ensure that commuters using the NSL could still continue on their journeys, SMRT redirected some trains from the East-West Line (EWL) to the NSL. This allowed train services to continue operating throughout the day on both lines, but with a longer interval between trains during peak hours. SMRT also activated free regular and free bridging buses along the busiest stretch of the to provide commuters with an alternative travel option. As there were fewer trains during peak periods, commuters experienced longer waiting times at the stations, but their travel times were largely unaffected once they boarded the train. 

5.     Meanwhile, SMRT had continued with their recovery efforts to move the stalled engineering vehicle. Due to the tight space around the depot tracks, SMRT was unable to use heavy lifting cranes. It had to use hydraulic equipment to slowly and safely shift the stalled vehicle onto another track. The stalled vehicle was cleared off the railway crossing by around 5.30pm. After completing a series of thorough checks to ensure safety, SMRT was able to launch trains from Bishan Depot from 6.36pm, and progressively restored normal train service for commuters on the NSL and EWL.

NEL incident on 10 Feb

6.     Next, the North East Line (NEL) incident on 10 February. At around 6.08 am, a signalling fault occurred near Buangkok station. This prevented the NEL trains from being controlled automatically. As a result, while trains could still travel along the NEL, they had to be controlled manually and travel at slower speeds to ensure safety. This led to reduced frequency of service and additional travel time for commuters. In response to this decrease in service capacity, SBS Transit (SBST) activated free regular and bridging buses along the NEL between Punggol Coast and Dhoby Ghaut stations at 6.55 am, to provide commuters with an alternative travel option.

7.     Preliminary investigations indicate that the signalling fault was caused by a malfunctioning electronic card in the signalling system. There were no prior signs during the maintenance checks which showed that this card would malfunction. SBST replaced the malfunctioning electronic card, and was able to restore the signalling system’s operations at around 8.00 am, following which normal train service was progressively restored. The faulty electronic card has been sent to the system manufacturer for further examination, to identify the root cause of the malfunction.

Circle Line incident on 11 Feb

8.     Third, the Circle Line (CCL) incident on 11 February. In LTA’s earlier statement on 13 February 2025, it noted that a power trip had occurred arising from a signalling fault. Further investigations show that there was no power trip, and that the incident was due to a signalling fault. 

9.     Based on LTA’s latest findings, at around 8.15 am, a signalling fault caused a temporary loss of communications between a CCL train and the trackside signalling equipment. When this happens, the incident train will engage its brakes and stop moving, in accordance with safety protocols. The other trains near the incident train will also come to a stop to ensure safety for commuters, by keeping the trains at a safe distance from one another until communications can be fully restored. 

10.    Due to this signalling fault, 17 trains between Paya Lebar and Marymount stations were temporarily halted for safety. SMRT promptly withdrew the incident train from the mainline, and after doing the necessary safety checks, train movement resumed progressively from 8.20am, 5 minutes after the signalling fault first occurred. 

11.    However, when train operations were being restored, SMRT noticed that the Central Automatic Train Supervision (CATS) System, which manages the movement of trains, became less responsive. As a result, it took longer than usual to resume normal train operations, even though trains had started moving on the CCL. The delay in resumption of normal train operations led to longer wait times and travel durations for some CCL commuters. 

12.    We had experienced a similar issue with the CATS system in September 2024. After that incident, LTA and SMRT worked with the system manufacturer Alstom to develop a software patch to address the issue. The patch went through extensive testing, and was ready for deployment on 15 February. Unfortunately, the incident happened a few days before the deployment date. SMRT and Alstom have since successfully deployed the software patch. 

13.    Mr Speaker, we take every incident on the MRT network seriously because rail safety, reliability and resilience will always be our priorities. Not just for LTA, but also for our tripartite partners in the One Transport Family. Our preliminary findings show that the three incidents were unrelated – they involve different lines, different components, and different operations and maintenance teams. Unlike some previous disruptions where trains were unable to continue travelling on the tracks, the three incidents did not result in a prolonged stoppage of train services. Trains could continue to run along the NSL, NEL and CCL, albeit at longer intervals or slower speeds. However, as these incidents happened during the morning peak hours, they affected a larger number of commuters and lengthened the waiting and travel times.

Reliability of our MRT network

14.    We recognise that every incident causes inconvenience for affected commuters. While we cannot completely prevent incidents from happening in a rail system of this size and complexity, we will do our best together with the operators and our workers to maintain a high level of safety, reliability and resilience, and to minimise the impact to commuters when an incident occurs.

15.    Through this approach, we have achieved our one million MKBF target consistently since 2019, which puts our overall system among the best performing metros of the world. As at 25 February 2025, the MKBF for our MRT network stands at about two million train-kilometres, and all MRT lines have achieved our target MKBF of at least one million train-kilometres. 

16.    Rail safety, reliability and resilience are key priorities for LTA and our tripartite partners. We will continue to work close together on this front to identify areas for improvement, adopt new technologies for more effective maintenance and operations, and invest in the skills of our workers.