All existing MRT lines to have system to detect overheating train axle boxes by 2028

SINGAPORE – A system to detect the overheating of axle boxes – undercarriage parts linked to a train’s wheels – will be installed on all existing MRT lines here by 2028.

These are the North-South, East-West, Circle, Thomson-East Coast, Downtown and North East lines.

The system will be set up on the Jurong Region Line (JRL) by end-2030, the Land Transport Authority (LTA) said in a Facebook post on Aug 3.

JRL will start operations in stages between mid-2028 and 2029, with a new station between Tengah and Choa Chu Kang set to open in the mid-2030s.

The axle box, which contains the axle bearings and connects the wheels to an axle rod, was at the centre of a major six-day rail disruption on the East-West Line (EWL) in September 2024.

Valued at about $12.5 million, the contract to install the new system was awarded to Chinese railway safety equipment manufacturer Chengdu Shengkai Co. The system will monitor the axle box and gearbox temperatures of passing trains via trackside infrared sensors. Installation is expected to start in 2027.

The system will alert rail operators to any abnormal temperature increase, so that necessary recovery steps can be taken to prevent faults from developing further.

It will also replace existing systems that detect overheating axle boxes across the rail network to standardise the designs and parts used. LTA noted that this move would also streamline the management of spare parts and provision of technical support.

At present, hot axle detection systems are already installed by operator SMRT on its North-South and East-West lines (NSEWL), and operator SBS Transit for the North East Line.

Two complementary systems will also be installed along with the new detection system to improve fault detection capabilities.

First, an acoustic detection system – installed only on the NSEWL and JRL – will use trackside microphone sensors and predictive analytics to spot early-stage damage to axle bearings.

The other system is a hot wheel detection system that monitors wheel temperatures of passing trains to allow the early detection of wheel and brake-related faults. This will be installed on all lines, including the JRL.

Axle bearings are mechanical parts that allow the smooth rotation of the wheels.

Excess friction within the axle bearings, due to degraded grease or deterioration of the rubber of the chevron springs, for instance, could lead to the overheating of an axle box.

Chevron springs are metal plates bonded together by rubber that absorb vibrations on moving trains.

The LTA tender for the supply of the hot axle box detection system was launched in October 2025, and closed in January 2026.

The Cross Island Line, which will be ready from 2030, was not included in this tender, as it is still under construction.

In the major incident on Sept 25, 2024, a section of a train’s carriage derailed after the axle box fell out.

Extensive damage was caused to 2.55km of track and trackside equipment as the train was withdrawn to Ulu Pandan Depot.

This crippled MRT services between the EWL’s Jurong East and Buona Vista stations for six days.

Based on findings from investigators, a sensor detected that an axle box on the train had reached a temperature of 118 deg C on the morning of the incident – above the typical operating temperature of 30 deg C to 65 deg C.

But owing to system issues, SMRT’s heat detection tool could not identify the train that experienced the temperature increase. These system issues were later rectified.