East-West Line disruption (Sep 2024)
Bridging buses deployed between Jurong East and Buona Vista
Date	25 September 2024
Location	Between Dover MRT and Ulu Pandan Depot
Rail line	East West Line
Operator	SMRT Trains
Type of incident	Train car derailment & extensive damage to permanent way
Cause	Dislodged train axle box
Train involved	Kawasaki Heavy Industries C151 (065/066)
Injuries	NA

On 25 September 2024, a major disruption occurred on the East-West Line when a defective axle box was dislodged from a KHI C151 train, causing one bogie to come off the running rail between Dover and Clementi stations. This caused extensive damage to the running rails, with rail breaks found across 2.55 kilometres of track, along with damage to rail fasteners, the third rail, power cables and point machines.

Due to extensive damage, train services were disrupted for six days (25–30 Sep 2024) with normal train services only resuming on 1 October. This was among the longest MRT train disruptions in Singapore’s history and the longest since 2017. About 500,000 out of 2.8 million train journeys were affected on each day of the disruption.

Incident Background:

The disruption began around 9 a.m. on 25 September 2024, when a first-generation Kawasaki Heavy Industries C151 train (Set 065/066) experienced a fault near Clementi station. A power trip occurred and smoke was emitted. Passengers on the eastbound train disembarked at the station, and SMRT subsequently withdrew the train from service by rerouting it onto the westbound track at Queenstown station.

While the train was heading back to the Ulu Pandan Depot near Dover station, a defective axle box on the third carriage fell onto the tracks. This caused one of the bogies to derail, which led to a trail of significant damage to both the tracks and nearby trackside equipment. The train eventually came to a stop along the eastbound reception track heading into Ulu Pandan Depot.

The derailment and resultant track damage caused a power trip around 9:25 a.m., causing the incident train to stall between the reception track and the main line. As this section of third rail was linked to the same power supply that serves the third rail on the eastbound track, the power supply to the eastbound track was thus also tripped.

The power trip caused four other trains between Clementi and Buona Vista stations to stall. Three of these were at stations, where commuters could alight at the platforms. One of the trains stalled about 40 meters before the platform at Clementi station, and as a result, approximately 850 passengers were detained onto the tracks and guided back to Clementi station.

Passengers detrain near Clementi station following the power fault (Online photo)

Damage to EWL permanent way (Photos: SMRT, published by Straits Times)

The incident caused train services between Boon Lay and Queenstown to be disrupted.

Train involved

The train involved in the incident was a first-generation Kawasaki Heavy Industries C151 train (Set 065/066). It was one of 66 trainsets manufactured between 1986 and 1989 for the North-South and East-West Lines, and had been in service for more than 35 years.

Train 065/066 damaged axle box and rails (LTA diagram)

Notably, set 065/066 was one of six C151 trains to be upgraded with PMSM traction motors back in 2017. This involved replacing the ageing traction motors and control electronics with modern equivalents that were more energy-efficient and easier to maintain. It is not known if these modification works would have contributed to the structural failure of the axle box.

What is an axle box?

Axle boxes are used to transfer the load of the train from the carriage to the wheels. Each axle of the train has an axle box at each end.

The axle box that failed was on the third carriage of the six-car train. This was identified as train car 2065. The middle carriages of NSEWL trains are motor cars; meaning that these bogie wheels are driven by an electric traction motor.

Location of the axle box on a KHI C151 train

Labelled components of a KHI C151 train bogie, with the axle box indicated in red

When one of the axle boxes dislodged from the incident train, it caused the wheels of the bogie to shift to the side of the rail. As the other eleven bogies of the incident train remained on the rails, the train was able to continue travelling for a few minutes on the rails westbound past Clementi.

Dropped axle box from KHI C151 train 065/066 (Straits Times Graphics)

The dropped axle box was later found beside the tracks near Dover station.

Damage to tracks & trackside equipment

LTA and SMRT discovered 34 rail fractures, including cracks and chips, along a 1.6 km stretch of track between Clementi and Dover stations. 33 severely damaged rail segments, each weighing more than one tonne, had to be replaced.

The derailed train also damaged three point machines, which are used to mechanically operate rail switches, and also dislodged several rail fasteners. One point machine, located between Jurong and Clementi stations, was so severely damaged that it could not be salvaged and needed replacement.

Sections of the third rail along the eastbound track were also damaged. The third rail provides electric power to the trains.

Damage to tracks & trackside equipment [Diagram: LTA/SMRT]

C151 Train Car 2065 derailed near Ulu Pandan Train Depot

On 29 September, an additional 12 cracks were found on unreplaced rail segments between Clementi station and the track crossover to Ulu Pandan Depot. This necessitated the replacement of another 10 rail segments, for a total of 2.55 km of rail that needed replacement. This pushed back the full restoration of train services from 30 September to 1 October.

Detailed location of EWL rail cracks [Diagram: Straits Times]

Service Recovery:

Day 1 (Wednesday, 25 September 2024):

Following the power trip at 9.25am, free regular bus services were activated between Boon Lay and Queenstown at around 9:30am. Free bridging buses were also activated between Boon Lay and Queenstown at 9:50am. The bridging buses arrived from 9:58am onwards.

Later in the afternoon, SMRT and the Land Transport Authority (LTA) provided more details about the incident, acknowledging the extensive damage and confirming that train services would not fully resume for the rest of the day. Heavy rainfall further delayed recovery efforts.

Partial train service was restored using shuttle trains between Buona Vista and Queenstown at 3.56pm, as well as between Jurong East and Boon Lay at 4.11pm; both at 10-minute intervals. Bridging bus services were later adjusted to run between Jurong East and Buona Vista, while regular bus services between Boon Lay and Queenstown remained free. This arrangement would continue over the next few days (until 30 September).

EWL disruption overview (25-30 Sep 2024)

By the evening peak, the number of bridging buses was increased from 39 before the peak period to 70, with an average interval of 3 to 8 minutes. This was quicker than the stipulated service standards of 12 to 15 minutes for bridging bus services. Additional spare buses were deployed and some bus captains on rest days were recalled.

At around 9:50pm, SMRT and LTA announced that the disruption would extend into the following day, and overnight checks would be performed on all first-generation KHI C151 trains before passenger service.

Day 2 (Thursday, 26 September 2024):

On 26 September 2024, LTA and SMRT revealed that 34 rail fractures had been identified along a 1.6-kilometre stretch of track. The incident also caused damage to three point machines, the third rail, power cables, and rail clips. Repair efforts continued throughout the day.

All Kawasaki Heavy Industries C151 trains in service that day had undergone and passed axle box functionality checks to ensure safe operations.

SMRT also reported that around 600 personnel from various organizations, including SMRT, LTA, other Public Transport Operators, the Public Transport Security Command (TransCom), and the Traffic Police, were involved in managing the crowds. About 80 double-deck buses were also deployed by SBS Transit, SMRT and Tower Transit to provide free bus bridging services between Buona Vista and Jurong East.

In the evening, LTA and SMRT announced that plans to partially restore train services between Jurong East and Buona Vista on Friday, 27 September, had been scrapped. Instead, the focus would remain on repairing the damaged tracks to restore full service by 30 September. Although they had considered operating a 20-minute shuttle train between Jurong East and Buona Vista, this option would have slowed down the repair work, potentially delaying full restoration by several days. The decision was thus made to prioritise repair and expedite restoring full EWL service.

Day 3 (Friday, 27 September 2024):

On 27 September, LTA and SMRT teams, along with contractors, continued working to replace the damaged tracks. Due to the rail fractures, engineers had to manually move new rails into place using mechanical jigs, as engineering vehicles could not be used. Fortunately, weather conditions were favourable, allowing progress in replacing power cables and two out of the three damaged point machines.

Restoration of the power rails was on schedule to be completed by Saturday morning.

Day 4 (Saturday, 28 September 2024):

LTA and SMRT teams continued working through the night and morning, making significant progress, including completing heavy rail delivery work. Efforts focused on replacing cracked rails along the 1.6 km stretch between Clementi and Dover, as well as repairing damaged track equipment. Shuttle trains, along with free bus services, continued to operate along the affected stations.

As of 7 p.m. on 28 September, all three track point machines and associated trackside equipment were repaired and had passed functionality tests. Power rails were also replaced, marking the completion of restoration work. SMRT planned to conduct comprehensive system functional and safety tests the next day, including checks on tracks, power supply, and train signalling. Trains would also be tested at various speeds throughout the next day.

Day 5 (Sunday, 29 September 2024):

Despite the completion of repairs on 28 September, additional cracks were discovered during stress and load tests. 12 new cracks, previously not visible to the naked eye, were detected on 10 unreplaced segments of running rail after these tests, likely weakened by the damaged train.

These new cracks meant that more repairs and testing would be necessary, delaying the reopening of the EWL. SMRT and LTA extended the service disruption to 1 October 2024.

Day 6 (Monday, 30 September 2024):

All affected rail segments between Clementi and Ulu Pandan Depot were successfully replaced overnight, and the third rail was reinstated. Several critical tests were completed, including the locomotive stress test, electric meggering test, and track circuit tests. The stress test ensured the structural integrity of the repaired rails, while electric meggering verified the electrical insulation of the third rail, allowing traction power to be safely restored.

Simulating the weight of a fully loaded train using sandbags, engineers conducted a loaded train endurance run to ensure the track’s strength and stability. With these tests completed, the system was prepared for the final stages of testing and passenger service.

That evening, SMRT and LTA announced that train services were ready to resume the following day (1 October). For safety reasons, westbound trains between Dover and Clementi stations would operate at a reduced speed of 40 km/h for three days, from October 1 to 3, to ensure safe travel on the repaired tracks. Commuters were advised to plan for an additional five minutes of travel time if travelling to the west on the East-West Line.

Day 7 (Tuesday, 1 October 2024):

Train services resumed on 1 October 2024.

SMRT implemented nightly inspections of newly replaced sections of rail between Jurong East and Buona Vista to ensure no further issues or defects arose, including using ultrasonic testing on every new welding joint. These increased inspections lasted for around a week before track inspections returned to the usual weekly schedule.

Recovery process

To recover the derailed train, the front two carriages (Car 3065-2065) were first uncoupled and pulled into Ulu Pandan Depot using a diesel locomotive. A temporary axle box was attached to the derailed train car before using a hydraulic system to rerail the carriage. Only then could the remaining train cars be pulled into Ulu Pandan Depot on the morning of 26 September.

On the night of 29 September, the derailed train car 2065 was transported from Ulu Pandan Depot to Tuas Depot by road.

Defective train left cracked rail, damaged power cables in its wake on EWL stretch | The Straits Times

Mobilisation of rail workers

More than 800 workers were mobilised between 25–30 September to repair the damaged rails, power cables, and trackside equipment.

SMRT deployed around 500 workers, including its entire track maintenance team, working around the clock in two 12-hour shifts. The LTA brought in 300 additional workers from external contractors engaged in other active rail projects, such as the Jurong Region Line and Circle Line Stage 6 extension. These workers operated in three shifts of eight to ten hours each. At its peak, 100 workers were stationed on the viaducts between Jurong East and Buona Vista, solely focusing on replacing the cracked or chipped rail segments.

The work was divided between LTA and its contractors, who handled the rail replacements near Dover station, and SMRT, which focused on the area near Clementi station.

Challenges faced during rail repairs

The repair work faced multiple challenges. Rain made it difficult to weld replacement rails to existing tracks, as exposure to moisture can result in poor-quality welds. Workers had to be sheltered under tents, and lightning posed additional hazards due to the open environment on the viaducts. Wet conditions also made the rails and sleepers slippery, increasing the risk of accidents.

On days without rain, extreme heat became another obstacle. High temperatures between 10 am and 3 pm caused the rails to expand, making rail-cutting difficult, as rail saws would often get stuck. The heat generated by welding equipment, which can reach up to 2,000 degrees Celsius, further complicated the work.

Welding of new rails (LTA Facebook; 28 Sep 2024)

Replacement rails being manually transported to the worksite (SMRT Facebook; 28 Sep 2024)

In addition, space on the rail viaducts was limited, exacerbating the challenges posed by the extensive track damage. Normally, engineering vehicles could deliver new rail segments directly to the replacement sites. However, with the rails damaged and power cut in the affected area, engineering vehicles could only deliver the rail segments to the nearest station (either Dover or Clementi). Workers then had to manually transport the new rail segments, each weighing around a tonne, using jigs which required eight workers to push. Each delivery took 30 to 45 minutes depending on the distance, with the farthest location being 600 to 700 meters from Dover station.

Shuttle Train services

Between 25 and 30 September 2024, shuttle train services were operated between Boon Lay and Jurong East, as well as between Buona Vista and Queenstown, at approximately 10-minute intervals.

Each shuttle train sector operated with two trains running back and forth on single tracks.

EWL shuttle train arrangement (Boon Lay – Jurong East)

EWL shuttle train arrangement (Buona Vista – Queenstown)

Sep 2024 EWL Disruption: Shuttle trains at Jurong East

Sep 2024 EWL Disruption: Shuttle train at Queenstown (Platform B)

Free Regular & Bridging Bus services

During the disruption period, free regular bus services were provided at designated bus stops and bus interchanges between Boon Lay and Queenstown. Free rides were offered on 85 bus services.

Free bridging bus services were offered between Jurong East and Buona Vista, with intermediate stops at Clementi and Dover stations. Around 80 bridging buses and at least 160 bus captains were deployed daily between Sept 25 and 30.

Contributions to the bridging bus fleet came from multiple operators: SBS Transit provided around 44 buses; Tower Transit provided 23 buses; SMRT Buses supplied 13 buses; and Go-Ahead Singapore offered 4 buses on 28 and 29 September. To cope with high passenger loads, the majority of buses deployed were double-deck buses.

EWL Bridging Bus boarding at Buona Vista MRT (Sep 2024)

These services followed existing EWL Bridging Bus arrangements, though the westbound bus boarding point at Buona Vista was temporarily relocated. Instead of Bus Stop 11369 (Buona Vista Station Exit D) along North Buona Vista Road, the boarding point was moved to the unused bus stop outside the Ministry of Education building further up the road, to improve queue management and reduce bus congestion at the main bus stop, which also serves nine regular bus routes.

Approximately 620 ground staff from the LTA, bus operators, and the police were deployed daily to manage operations. Teams were also stationed at bus stops and within affected MRT stations to guide commuters and provide assistance. LTA also ensured smooth operations by pausing roadworks along the bus routes and deploying enforcement officers to prevent illegal parking, keeping bus lanes clear.

SMRT, which operates the East-West Line, will cover the costs of the bus services. As of 2 October 2024, the company was in the process of calculating the total expense.

Disruption Impact

According to the Straits Times, the disruption affected more than 2.1 million passengers as of 30 September. This included about 358,000 passengers on 25 September, an estimated 516,000 on 26 September, some 500,000 on 27 September, and an estimated 374,000 on 28 September.

The disruption also coincided with the Primary School Leaving Examination (PSLE), which began on 26 September, affecting students sitting for the exams. The Singapore Examinations and Assessment Board (SEAB) publicly assured that students would not be penalized and that arrangements had been made for such situations. Affected candidates were advised to contact their schools for further assistance.

SMRT and LTA also arranged for chartered taxis to provide free rides for students and teachers travelling to PSLE examination venues from Jurong East, Clementi, Dover, and Buona Vista stations. This service was similarly provided for those travelling to their PSLE or N-level examination venues on 27 and 30 September.

On the morning of 26 September, five students arrived late for the English and Foundation English written exams due to the disruption. They all arrived before the end of the paper, were given time to settle, and were granted the full duration to complete their exams. One of the five students sat the examination at a different centre.

Public Reactions

The incident cast a negative spotlight on SMRT’s maintenance record, particularly since the North-South and East-West Lines had recently completed the upgrade of six core systems in October 2023. These systems included signalling, sleepers, power rails, power supply, track circuits, and rolling stock.

Early updates issued by SMRT, which specified the involvement of a first-generation Kawasaki Heavy Industries C151 train that had been in service for over 35 years, led some to question whether SMRT was attributing the incident to the train’s age to deflect from inadequate maintenance practices. It was noted that metro systems worldwide have successfully kept older trains in operation without experiencing similar structural failures in the bogie. Replacement of all C151 trains with new R151 trains is expected to be completed by end-2026.

This disruption also marked another significant incident on the East-West Line, following the 2017 train collision at Joo Koon caused by a fault in the newly implemented CBTC signalling system. Ironically, the East-West Line was SMRT’s most reliable rail line, boasting a mean kilometre between failures (MKBF) of 5.05 million train-kilometres in 1Q 2024, the highest reliability score among all SMRT-operated lines. MKBF measures rail reliability by calculating the average distance trains travel before experiencing delays of more than five minutes.

SMRT statement referencing KHI C151 trains in service for over 35 years (SMRT Facebook; 25 Oct 2024)

1Q 2024 MKBF figures for rail lines (LTA diagram)

Online attention was also drawn to a 2023 Straits Times article where SMRT chairman Seah Moon Ming emphasized the need to balance rail reliability with cost, stating, “We don’t want overmaintenance.” This comment was criticised in light of the current disruption, as many believed SMRT had failed to adequately maintain its trains.

The disruption also occurred weeks after a planned 6% increase in public transport fares was announced, effective December 2024. SMRT applied for the maximum allowable fare hike, and some commenters remarked that such fare increases were unjustified, as they had not translated into better rail reliability.

Investigation

On 2 October 2024, a week after the disruption began, LTA announced that it had commenced regulatory investigations into the disruption.

The scope of the investigation will focus on three key areas. First, LTA will investigate the root cause of the axle box failure that triggered the incident. This includes a forensic analysis to understand the nature of the failure and identify any contributing factors.

Second, the investigation will examine the fault detection and incident handling procedures. LTA will assess whether the proper actions were taken during the incident, review current procedures, and suggest improvements to prevent similar disruptions and damage to rail infrastructure in the future.

Third, LTA will evaluate the service recovery and disruption mitigation efforts. This review will look into the operator’s response, including the timeliness of bridging bus deployment, the effectiveness of disruption announcements, the guidance provided to commuters on alternative travel options, and overall crowd management.

LTA to Conduct Thorough Investigations Into the Root Cause of the Disruption of Services on East-West Line | LTA

Parliamentary Ministerial Statement on 15 October

In a Ministerial Statement delivered on 15 October 2024, Transport Minister Chee Hong Tat addressed several questions raised by Members of Parliament regarding the train service disruption.

Firstly, on the structural integrity of the trains, the Minister explained that an independent assessor 2012 concluded that the KHI C151 trains have a total service life of 38 years. Under the New Rail Financing Framework, the Land Transport Authority (LTA) decided to purchase new R151 trains to replace the C151 fleet. The plan is to phase out all C151 trains by the end of 2026, before they reach their 38-year lifespan.

In terms of compensation for affected commuters, the Minister clarified that passengers exiting at stations between Boon Lay and Queenstown were not charged for their rail journeys, and free bridging and regular bus services were provided along the affected sector. For cases where commuters were charged for two journeys instead of one—due to exceeding the 45-minute transfer window between train and bus services or between different buses—SimplyGo has been processing refunds.

Regarding whether service disruptions should influence the Fare Review Exercise conducted by the Public Transport Council (PTC), the Minister noted that PTC had previously examined this issue but chose not to link fare adjustments to service levels. Instead, existing mechanisms ensure that service standards are met. For service disruptions, LTA investigates the cause, holds operators accountable, and applies penalties when necessary. Moreover, operators failing to meet reliability targets do not receive payments under incentive schemes. The Fare Review Exercise is intended to ensure that fares reflect changes in operating costs to maintain the financial sustainability of the public transport system, independent of service quality or disruptions.

Finally, the Minister addressed the cost implications of the disruption, stating that SMRT will cover the costs regardless of the investigation’s outcome, including those for the free bus services, lost fare revenue, and repair works. This rule applies to all rail operators in the event of a disruption on their respective lines. LTA and SMRT staff who worked overtime during the disruption would also receive appropriate overtime payments.

On the safety, reliability, and resilience of the MRT

On safety, the Minister emphasised that it remains a top priority and will never be compromised. The LTA enforces strict safety standards and regularly audits rail operators to ensure compliance. Redundancies are built into key systems, and established processes are in place to manage and respond to emergencies.

On reliability, the Minister noted that all MRT lines surpass the target of 1 million train-kilometres MKBF, a significant improvement from the 67,000 train-km average in 2012. This progress is credited to the efforts of rail operators and workers over the past decade, and key infrastructure upgrades done by LTA.

On resilience, the Minister praised the efforts of bus operators and ground staff in managing the disruption, and affirmed LTA’s commitment to ongoing rail network expansions over the next decade that would increase capacity and provide more transport options, thereby improving resilience.