A major accident averted after a faulty signal brought Chennai Suburan trains too close to the same track

The railways recently sent out notices for an audit of signaling equipment across its network. File | Photo credit: The Hindu Bureau

A major accident was averted at Southern Railway’s Chennai division after an alert motorist braked when he noticed two trains already ahead on the same track.

A serious safety lapse occurred on the Ambattur-Avadi section on March 5, 2026. A multi-departmental inquiry has been ordered into the incident, official sources told The Hindu on Friday.

According to sources, an Electric Multiple Unit (EMU) commuter train approaching automatic signal S192 was flagged as “Double Yellow”, which entitles it to caution. As the train progressed, the driver noticed two trains standing on the same track in the visible distance. Realizing the potential danger, he immediately stopped the train just short of the signal, averting what could have been a serious accident.

A preliminary investigation found that the security system had malfunctioned and the wrong signal had been displayed, allowing the approaching commuter train to continue despite the track being occupied. Railway officials suspect that the incident was triggered by unauthorized resetting of the multi-section digital axle counter (MSDAC) by a technical staff member, sources said.

In a similar case of signaling failure on 28 June 2026, an express with about 900 passengers was cleared to proceed from Arakkonam towards Renigunta. However, due to incorrect setting of points, the train was inadvertently diverted towards Katpadi. After the locomotive pilots realized that the train was heading in the wrong direction, they stopped it and carefully put it back into Arakkonam.

Locomotive pilots express concern

Members of the All India Loco Running Staff Association have expressed concern over repeated signaling failures and said that the locomotive pilots and drivers were operating the trains solely based on the signaling aspects displayed on the track. Any incorrect signal, whether caused by a technical fault or human error, could endanger passenger safety and disrupt train operations.

The association noted that signaling failures have been identified as a contributing factor to several major train accidents in recent years. “Such incidents undermine the confidence of locomotive pilots and drivers who are totally dependent on the integrity of the signaling system for the operation of trains. The crew cannot be expected to work calmly if the reliability of the signaling system itself becomes questionable,” a senior locomotive pilot was quoted as saying in a letter sent to the association by Southern Railway.

Published – 11 July 2026 05:30 IST