26-9-2024 (SINGAPORE) Singapore’s leading transport operator, SMRT, has disclosed that a breach in standard protocol led to a significant disruption of train services on the Circle Line for nearly two hours on 17th September. The revelation comes amidst ongoing challenges on the East-West Line, where regular train services between Boon Lay and Queenstown stations have been suspended since Wednesday.
In a detailed Facebook post, SMRT shed light on its investigations into two separate Circle Line disruptions that occurred last week. The transport operator’s transparency comes at a crucial time, as commuters grapple with the inconvenience of service interruptions across the network.
The 17th September incident, which unfolded during the evening rush hour, was triggered by a tripped circuit breaker on the traction safety shutdown system (TSSS), a critical component responsible for monitoring safe train operations. SMRT’s maintenance team, in their eagerness to prevent potential future disruptions, initiated corrective measures without adhering to the standard protocol of seeking clearance from the head of Circle Line operations.
“Our standard protocol requires the maintenance team to seek clearance from the head of Circle Line operations before conducting corrective maintenance during service hours,” SMRT explained. “This step ensures that maintenance in a live system is carefully controlled. Unfortunately, in their eagerness to rectify the fault, the team overlooked this critical step.”
The oversight led to a cascading effect, causing another circuit breaker to trip and resulting in a loss of traction power across the entire Circle Line. SMRT acknowledged that such corrective actions should have been reserved for engineering hours when train services are not operational.
The transport operator also addressed the extended duration of the service disruption, citing the need for thorough safety checks before resuming normal operations. “For the safety of our commuters, the operations control centre had to account for all trains before normal services could resume,” SMRT stated.
During the disruption, SMRT implemented diversion plans and advised commuters to utilise alternative MRT lines or buses. In-train and station announcements were made consistently, barring a brief 12-minute interruption due to a technical glitch in the public announcement system.
SMRT engineers, in collaboration with the Land Transport Authority (LTA) and Original Equipment Manufacturer (OEM) engineers, worked through the night to diagnose and resolve the issue, ensuring normal train services resumed as scheduled the following morning.
The transport operator also provided details on a separate incident that occurred on 18th September, involving a fire in a TSSS cubicle at Kim Chuan Depot. This incident triggered an automatic line-wide power shutdown through the global emergency shutdown system. While the fire was swiftly extinguished and services resumed within 15 minutes, SMRT noted that the cause of the fire remains under investigation.
In response to these incidents, SMRT has announced a comprehensive review of the TSSS and global emergency shutdown systems in collaboration with LTA. Planned improvements include enhancements to the Circle Line’s signalling and public announcement systems, as well as upgrades to fail-safe and fail-soft features.
“The procurement of a replacement TSSS cubicle, with enhanced features, is being expedited,” SMRT assured the public, underlining its commitment to preventing similar disruptions in the future.
