Two days after Monday's train disaster at Sainthia in Birbhum district, the cause of the collision that snuffed out 66 lives still remains a riddle.
With both the driver and assistant driver of 3148 Dn Uttarbanga Express having died when their train rammed into the 3404 Dn Vananchal Express from behind at high speed at Sainthia station, it is difficult to ascertain what exactly happened in the last few minutes at around 1.54 am.
Though the Uttarbanga Express had a scheduled stop at Sainthia station, it entered the platform at very high speed and hit the rear of the Vananchal Express, which had moved 100 metres and then stopped again.
In a manual interlocking system area, according to standard Indian Railway norms, when a train enters a station, the home signal for the line immediately becomes red and remains so till it leaves the station and the outer cabin of the station.
After the outer cabin confirms the departure of the last compartment of the train to the station master, the home signal again turns green for another incoming train.
In this case, the home signal was supposed to be red, as the Vananchal Express had not yet left the station, let alone the outer cabin signal.
But the fact is, even if the signal was green due to cabin man or technical error, the incoming Uttarbanga Express had to slow down to around 20 km per hour while entering the platform to stop at the station.
Instead, the Uttarbanga Express entered at over 60 km per hour speed and hit the stationary Vananchal Express from behind.
Keeping the possibility of a driver ignoring the signal or some other technical fault in mind, the railway has a second safety measure in place.
As soon as a train enters a station, the point on the lines are set to another track which is free of traffic or to the dead end line to ensure that it is diverted to the other line to prevent it from ramming into the one standing ahead.
The setting of point to another line is done by the stationmaster on duty.
In this case, this procedure was apparently ignored by the station master.
However, there is no denying that the initial and main reason for the accident was that the driver Madhab Chandra De and assistant driver Nirmal Mondal of Uttarbanga Express had not slowed down despite Sainthia being a scheduled stop.
Had the drivers slowed the train to the stipulated speed of below 20 km per hour while entering the platform, they could have applied the emergency brakes and stopped it as the Vananchal Express had moved ahead and its last compartment was more than half way through the platform.
On the day of accident, General Manager of Eastern Railway V N Tripathi had told PTI "the train was at speed".
He had said that the driver had an unblemished record of five years of driving express trains.
"We are also puzzled how it happened and only after an inquiry by commissioner of railway safety will we be able to ascertain to cause."
Several theories are doing the rounds on the reason for the driver and assistant driver not bringing the train to a halt. This ranges from both De and Mondal having fallen asleep to their being drugged or for some technical fault in the diesel engine like failure of the brake.
But had the brakes failed, they would have informed the guard of their train over walkie-talkie. It has been claimed that the guard had made frantic calls to De and Mondal, but they did not respond.
The time between 2 am and 4 am is very crucial and this is when people tend to feel sleepy. Many accidents have occurred during this time period, a railway source said, adding two drivers are engaged on duty for operational reasons and also to ensure that they remain awake by talking to each other or in an extreme situation at least one is awake.
It is possible that by sheer coincidence, both of them had fallen asleep at the same time, leading to the train ramming into the other from behind. The other remote possibility is their being drugged by design or by fault.
There have been several incidents in the eastern sector where passengers were robbed after being drugged.
The modus operandi of the robbers is to befriend passengers and then offer food, sweets or tea laced with drugs. The unsuspecting passengers after taking the food either fall asleep or becomes senseless following which they are robbed.
It may be a remote possibility that some thug, posing as a hawker had sold the driver and assistant driver tea or snacks laced with drugs.
The serving of the drug-laced tea or food to the drivers could have been by accident, as there was almost no possibility of robbing them, or it could have been a sinister design.
The police have registered a case under sections 279 (rash driving), 337 and 338 (causing hurt/grievous hurt by act endangering life or personal safety of others), 427 (mischief causing damage) and 304(a) (causing death by negligence) of IPC, West Bengal DGP Bhupinder Singh has said.
The viscera report of De and Mondal, which could throw light on any such possibility, has not yet been received, a top Birbhum district police official told PTI.
While the commissioner of railway safety of Indian Railway is holding an inquiry, the West Bengal Central Investigation Department has also registered a case and started an investigation into the cause of the accident.
