SMRT will progressively roll out new upgrades across 92 trains on Singapore’s rail network, introducing improved air-conditioning systems and advanced sensors to detect potential faults before they turn into major disruptions. The transport operator announced the plans on Thursday (Dec 18), saying the upgrades are meant to enhance rail reliability and improve commuter comfort.
The enhancements are based on a prototype train developed by STRIDES Technologies, an SMRT subsidiary. This prototype is currently being tested on a C151B train running on the North-South and East-West lines.
Sensors to Detect Faults Early
The upgraded train is equipped with an additional 180 sensors installed throughout various parts of the train. These sensors monitor key variables such as cabin temperature and mechanical performance, sending data in real time to a maintenance control centre located at the Bishan depot.
According to SMRT, the system can detect 47 warning signs that may lead to faults, including issues related to braking, door opening and closing times, and other critical components. Maintenance teams can then act early, either while the train is still in operation or after it has completed its service for the day.
“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.”
Testing and Rollout Timeline
The prototype train was developed under a proof-of-concept contract signed between SMRT and the Chinese railway company CRRC Sifang in November last year. Modification works began in the first half of 2025 at CRRC Sifang’s facility in Qingdao, China, followed by testing between August and September.
The train cars arrived in Singapore in October and have since undergone local testing and commissioning. SMRT aims to launch the upgraded train for passenger service on the North-South and East-West lines in June 2026.
Once the prototype is validated, the Land Transport Authority will work with SMRT to roll out the upgrades to 91 other trains. In total, 35 C151A trains, 45 C151B trains and 12 C151C trains will be upgraded, with works expected to be completed by the mid-2030s.
Improved Air-Conditioning System
The prototype train also features a new air-conditioning and ventilation system. SMRT said the existing system is “ageing and unable to sustain its intended cooling capacity”.
The replacement system uses modern, high-efficiency components designed for better durability and reliability. It also uses a refrigerant with a lower global warming potential to reduce environmental impact. Sensors embedded within the system can detect filter blockages and leaks, allowing proactive maintenance. Cabin temperature sensors will alert the control centre if conditions become too warm or cold, enabling remote adjustments.
Monitoring Doors and Bogies in Real Time
Beyond air-conditioning, the upgraded system will monitor train doors, power systems, brakes and bogies in real time. The bogie monitoring system tracks wheel wear, axle load, temperature, vibration and structural integrity. Early signs of degradation, such as 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,” SMRT said.
Currently, bogie issues are often detected only after commuter feedback. Undetected faults have previously caused major disruptions, including a six-day East-West Line disruption in September last year.
Train doors will also be monitored more precisely, allowing maintenance teams to identify the exact door with a fault instead of inspecting multiple sets.
“SMRT is taking a proactive approach to improving rail reliability through a better understanding of the latest technologies,” the operator said.
