Singapore rail operator SMRT has announced plans to progressively upgrade 92 MRT trains with improved air-conditioning systems and advanced sensor-based monitoring technologies, aimed at enhancing rail reliability and reducing service disruptions across the network. The initiative is based on a new prototype train developed by STRIDES Technologies, an SMRT subsidiary, and will be rolled out following regulatory validation.
The upgraded trains will be equipped with an additional 180 sensors installed across critical onboard systems, enabling real-time monitoring of cabin temperature, doors, brakes, bogies, power systems, and air-conditioning units. These sensors can detect up to 47 early indicators of potential faults, allowing maintenance teams to intervene before issues escalate into service-affecting incidents. Data from the sensors will be transmitted in real time to a maintenance control centre at Bishan Depot, supporting predictive maintenance and operational adjustments while trains remain in service.
The first upgraded unit is a fifth-generation C151B train currently undergoing testing on the North-South and East-West lines. 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 returned to Singapore in October 2025 for local testing and commissioning, with plans to introduce it into passenger service by June 2026. Subject to approval, the programme will be extended to 91 additional trains, including 35 C151A, 45 C151B, and 12 C151C units, with fleet-wide upgrades expected to be completed by the mid-2030s.
A key component of the upgrade is the replacement of ageing air-conditioning and ventilation systems with modern, high-efficiency units using refrigerants with lower global warming potential. Embedded sensors will monitor filter conditions, leaks, and cabin temperatures, enabling proactive maintenance and remote adjustments for passenger comfort. The programme also introduces real-time bogie monitoring, tracking parameters such as wheel wear, axle load, vibration, and temperature to detect early signs of degradation and prevent costly failures.
SMRT stated that the initiative reflects a broader shift towards predictive maintenance and technology-led reliability improvements, supporting future network expansion and rising commuter demand while improving ride comfort and reducing unplanned downtime.