Calcutta, July 20: Railway officials today claimed the two drivers of the Uttar Banga Express may have been drugged by a tea vendor, preventing them from acting to avert a collision with the Vananchal Express at Sainthia station yesterday.

Preliminary investigations have thrown up “evidence” that driver Madhab Chandra Dey and his assistant Nirmal Kumar Mandal had drunk tea during their previous, two-minute stopover at Gadadharpur station, 7.5km from Sainthia, senior officials said.

Whether the tea was spiked, though, appears to be conjecture at this point. Only a viscera report, which will take seven to 15 days to arrive, can establish drugging.

The drug theory was lent some credence, however, by the wife of Somnath Sengupta, the injured Uttar Banga guard.

“My husband had called me (from hospital) at 6.40pm yesterday. He said that when the train failed to slow down as it approached Sainthia yesterday, he had tried to speak to the drivers over the walkie-talkie. But one of them couldn’t speak at all while the other was groaning,” Sangeeta Sengupta told The Telegraph at her home in Malda.

Dey’s daughter Juthika Das, however, objected to railway officials’ endless conjectures surrounding the drivers and what she saw as their disparaging remarks, telling this newspaper that the family was feeling “insulted”.

Railway bosses had yesterday said there was “something wrong” with the drivers: they had sped along at 80-90kmph despite Sainthia being a scheduled stop, overshot the signal, eschewed the emergency brakes and not even tried to jump off to save themselves.

“All the information indicates sabotage,” a railway official said today, hinting at a political motive. “The drivers were drugged. Else, it would have to be a suicide pact between the duo. That’s absurd.”

However, if the drug theory turns out to be true, it will also open up an alternative possibility to sabotage — that the spiked tea was meant for passengers and reached the drivers by default.

Several gangs have been befriending and drugging train passengers in eastern India with spiked beverages and robbing them, and it’s possible that Dey and Mandal got their tea from one of these. These gangs operate across states and will be harder to catch than a local station vendor.

Pharmacology specialists said a person’s tea or soft drink could indeed be spiked with small amounts of certain drugs such as nitrazepam, which would not change the taste but put him to sleep in minutes, especially if his stomach was empty.

An alarmed railway board this morning issued a directive for drivers and guards, asking them not to buy or accept any beverages, not even tea or coffee, from any vendor or stranger while on duty.

The railways are also probing possible human error in operating the panel interlocking system at Sainthia.

“Once a train is put on a particular track, the (convergence/divergence) points behind it are set in such a way that if the next train flouts the signal, it will be diverted to another track. It seems the operator didn’t set the panels properly,” an official said.

Railway sources defended the Uttar Banga guard against criticism for not applying the guard’s brakes to stop the train.

“As a rule, we don’t encourage guards to apply full brakes. If the guard applies the brakes from the rear while the driver is running the train at full speed, the train can be snapped from the middle,” an official said. “The guard’s brakes are meant mainly as a signal for the drivers to stop.”

Sengupta, whom sleuths from the commissioner of railway safety met in hospital today, is in “trauma”, an official said. Chief minister Buddhadeb Bhattacharjee has ordered a CID probe.