The freak accident here in which two local trains collided head-on on Saturday night occurred after two chain-pulling incidents in a train forced the driver make an unscheduled halt, according to preliminary investigation by the railway authorities.

Official sources said an inquiry by the Commissioner of Railway Safety would throw light on the causes of the accident. But the authorities have discounted human error as the reason.

125 trains cancelled

Six persons were injured in the accident at Andheri at 11.10 p.m. in which three coaches derailed. Train schedules went haywire on the western line for some time. The official sources said 125 trains were cancelled and 160 delayed till Sunday evening. Trains were running late by at least 15 minutes.

“After the accident, only the two lines on which the accident occurred, were blocked. One of the lines was held up by the public. Normal traffic resumed immediately on the other lines. At 6.10 a.m. on Sunday, these two lines too were normalised before the peak hour started,” Sandeep Silas, Divisional Railway Manager, Western Railway, told The Hindu.

The official sources said a major tragedy was averted as one of the drivers showed presence of mind and applied the brakes immediately. “Thankfully, the trains were not running at very high speed,” an official said. The driver of a train hit the brakes when the two trains were around nine km away.

Some passengers pulled the chain on the Churchgate-bound local around 10.53 p.m. The driver halted the train and restarted. Again, some passengers pulled the chain. This time, the driver stopped a little ahead of the signal. Effectively, most of the coaches of the train were behind the signal, but the engine moved ahead. According to the rules, a route can be sent for cross-movement if the driver has cleared the signal. “There is eight to 13 metres overlap after the signal. If he stops within it, there is no indication that the train has stopped,” a senior officer said.

The train proceeded towards Churchgate at 11.04 p.m., but the route was chalked for cross-movement for a Virar-bound local. “The driver of the Churchgate-bound local realised that the point was not set for him and he immediately applied the brakes,” he said.

Three in hospitals

Meanwhile, the six injured were given ex-gratia payment by the railway authorities, Nitin David, Western Railways Public Relations Officer, said. “Three persons have suffered grievous injuries. They are admitted to two city hospitals. Three persons had minor injuries, they are not admitted.”

Mr. David said the grievously injured were given Rs. 5,000 each while those who suffered minor injuries got Rs. 500 each.