KUALA LUMPUR: Technical faults and loss of communications between a train hostler (driver) and the operations control centre (OCC) were identified as among the factors that led to the Kelana Jaya light rail transit (LRT) line train collision on May 24.
Transport Minister Datuk Seri Dr Wee Ka Siong, in explaining the scenario which led to the collision, said Train 40 had earlier experienced technical difficulties and one of the two of its Vehicle On-Board Communication (VOBC) system was halted at 6.26pm.
"The standby VOBC, as the standard redundant safety system of the LRT trains, then kicked in. In line with proper safety procedure, Train 40 was then vacated of passengers and remotely brought to the Lembah Subang depot via Automated Train Operation (ATO) mode for the necessary maintenance.
"However, at 8.13pm, the second VOBC on Train 40 halted and there was a lost of communication (time-out) with the OCC while it was en route to the Lembah Subang depot," he told a virtual press conference today.
The press conference was to reveal a probe report prepared by the investigation committee on the incident.
Wee said as a failsafe system, a train will come to a complete stop when it experiences a "time-out", which was the case for Train 40 that stopped between the KLCC and Kampung Baru LRT stations.
During this time-out, the OCC, however, was unable to detect and remotely control Train 40.
"A hostler was then called to manually reset both VOBCs and drive Train 40 to the 're-enter' point near the Dang Wangi LRT station (located after the Kampung Baru station, southbound), in an attempt to return the operation of Train 40 to ATO mode.
"During the process of resetting both VOBCs and driving Train 40 manually to the re-enter point, both the hostler and OCC's train controller had overlooked and missed critical procedures during this process."
This inadvertently resulted in Train 40 being manually moved northbound towards the KLCC LRT station, instead of southbound towards the designated re-entry point at the Dang Wangi station, he said.
At the same time, he said the other train, Train 81, which had passengers on board and was on the same track, was held back at the KLCC LRT station and a protective Manual Route Reservation (MRR) was implemented while Train 40's situation was being resolved.
However, the MRR was lifted and Train 81 was prematurely made to depart the KLCC station towards the Kampung Baru station without proper verification that Train 40 had been safely reset and re-entered into ATO mode, he said.
This led to the collision between Train 40 and Train 81, he added.
The May 24 collision between the two LRT trains led to 47 people being seriously injured and 166 others with minor injuries.