SMRT to upgrade 92 trains with improved air-conditioning, more sensors to preempt disruptions in real-time
The additional 180 sensors placed throughout the train will help detect early signs of faults and potentially prevent lengthy service disruptions.
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SINGAPORE: Train operator SMRT will progressively roll out new features such as an improved air-conditioning system and more timely detection of potential faults to 92 trains, in a move to enhance rail reliability, the transport operator said on Thursday (Dec 18).
These enhancements stem from a new prototype train being tested by STRIDES Technologies, an SMRT subsidiary.
By using an additional 180 sensors placed throughout the train, the system can detect early signs of faults and potentially prevent lengthy service disruptions. Variables such as cabin temperature will also be monitored in real time.
For now, the upgrades will be introduced on one C151B train operating on the North-South and East-West lines.
In November last year, SMRT and Chinese railway company CRRC Sifang established a "proof-of-concept" contract to trial these capabilities on the C151B train.
Modification works on the train began in the first half of 2025 at CRRC Sifang’s facility in Qingdao, China, with testing conducted there between August and September.
The train cars arrived in Singapore in October and have since undergone local testing and commissioning. The aim is to launch the upgraded train on the North-South and East-West lines in June 2026.
HOW THE NEW SYSTEM WORKS
All sensor data will be transmitted in real time to a maintenance control centre at the Bishan depot.
Potential faults will be flagged early, allowing maintenance teams to plan interventions before issues escalate.
Simple fixes such as adjusting aircon temperatures can be done as the train is operational, while for more serious faults, passengers could be asked to disembark so the train can be brought back to the depot.
Issues that are less serious can be rectified after the train has completed its daily service.
The new system can detect 47 signs that could lead to faults, ranging from braking issues to door opening and closing times.
“Sensors embedded in our trains enable us to detect potential issues before they become faults,” said Mr Andy Chiang, managing director of STRIDES Technologies.
“These timely alerts enhance rail reliability and deliver more comfortable journeys for everyone.”
Once the first train is validated, the Land Transport Authority will work with SMRT to roll out the upgrades to 91 other trains on the North-South and East-West lines.
In total, 92 trains will be upgraded: 35 fourth-generation C151A trains, 45 fifth-generation C151B trains and 12 sixth-generation C151C trains. The works are expected to be completed by the mid-2030s.
The prototype train will have a red and white livery, mirroring the colours of the Singapore flag.
AIRCON REPLACEMENT
The prototype train has a new air-conditioning and ventilation system. The previous system is “ageing and unable to sustain its intended cooling capacity”, said SMRT.
The upgraded system will use modern, high-efficiency components designed for durability and reliability, along with a refrigerant with lower global warming potential to reduce environmental impact.
Embedded sensors will detect filter blockages and leaks for proactive maintenance.
Cabin temperature sensors will also alert the control centre if conditions become too warm or cold, allowing remote adjustments for passenger comfort.
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DOORS, BOGIES TO BE MONITORED IN REAL TIME
There will also be a bogie monitoring system designed to continually monitor the condition of the critical bogie components.
A bogie is the undercarriage of a train, which houses the suspension systems, axles, gearboxes and wheels.
The monitoring system tracks parameters such as wheel wear, axle load, temperature, vibration, alignment, and structural integrity.
This means that early signs of degradation, such as through overheating, can be detected before a fault occurs.
“This system minimises unexpected downtime, keeps trains operating efficiently, and ensures a stable and comfortable ride for commuters,” said SMRT.
There are currently no on-board systems to monitor and feedback the condition of critical bogie components in real time. Issues with the bogies that could result in bumpier rides could instead be detected upon feedback from commuters.
A bogie with an undetected fault can result in costly disruptions.
In September last year, a six-day train disruption on the East-West Line occurred when a defective axle box on a first-generation KHI train dropped onto the tracks, causing a bogie to come off the running rail and damage the tracks.
Train doors will also be monitored in real time. At present, a door fault only indicates which cabin the defective door is located in, requiring maintenance staff to inspect multiple sets of doors.
The new system will pinpoint the exact door with a potential fault, speeding up repairs.
Beyond doors, the system will monitor power systems, air-conditioning units and brakes, among other components, issuing alerts whenever anomalies or potential faults are detected.
“SMRT is taking a proactive approach to improving rail reliability through a better understanding of the latest technologies, testing alternative solutions and enhancing commuter comfort,” the transport operator said.
“The intent is to identify faults before they happen. This is essential for futureproofing as well as meeting growing commuter demands as the rail network expands.”
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