A child whose parents went missing after the accident. (PTI)

Lucknow, Oct. 22: The chain-pulling that stopped the Mewar Express was being blamed today for the Mathura train tragedy, shifting the focus from possible driver error or signal failure to passenger mischief.

Mathura police said “a hardened criminal” being transported by the train had escaped around the time the chain was pulled, and minutes later the Goa Express had rammed the stationary train from behind, killing 23 people.

The police said undertrial Munna Sajid, 27, may himself have pulled the chain or his police escorts may have done so immediately after he had jumped off around 4.30am. A third theory suggests a passenger had woken up late to find the train had just passed his destination, Mathura, and pulled the chain — and that Munna had just taken advantage of the confusion.

Railway minister Mamata Banerjee seized on the “criminal offence” angle last night as she announced a CBI probe into the first major accident during her tenure that has raised questions about tracks safety, which she has been harping on.

Some of her own officials, however, said the ballyhoo over the chain-pulling — on which Mathura police have started a criminal case and which the CBI is expected to investigate — would divert attention away from serious safety issues.

“Chain-pulling is a non-issue. It is just one part of the accident. In Bihar this happens almost every day,” a senior North Central Railway official said.

“Not all incidents of chain-pulling cause accidents. If a train stops because of chain-pulling, another train should not come just rushing in from behind to collide with it.”

The collision happened eight minutes after the Delhi-bound Mewar Express had stopped near Bhuteswar station. Senior railway officials had said yesterday that the Goa Express driver was probably to blame, since he did not stop at the signal that would have automatically turned red as soon as the Mewar Express had stopped.

Even if the automatic block signalling system that does this had failed, that failure itself would have turned the signal red, the officials had said.

By last evening, however, the focus had shifted to the “criminal” angle after a Rajasthan police team that was on the Mewar Express approached Mathura police to register a case against Munna alias Rahim Ali, a robbery accused.

They said they were taking Munna from Kota to Delhi to produce him before a court.

The Mathura police said that after the train left Mathura station at 4.20, Munna had sought permission to go to the toilet. He may have pushed an escort aside and jumped off the train, which was moving slowly. Then, as the train speeded up, “the cops allegedly pulled the chain,” said B.D. Paulson, senior superintendent of police, Mathura. Or perhaps Munna himself pulled the chain, he added.

Mamata has ordered the transfer of Agra divisional railway manager and sent two technical officials on leave, a PTI report said.