As the massive triple train collision in Odisha indicated at a possible gap in the interlocking system of the signal, a similar incident that took place in February has now come to the fore. The driver identified the loophole and stopped the train - Sampark Kranti Express. The error was noted with caution. "If the signal maintenance system is not monitored and corrected immediately, then it would lead to happening of such re-occurrence and serious accidents," the note written by Hari Shankar Verma, principal chief operations manager, South Western Railway, said. Read | Passenger trains resume services on restored tracks after Odisha three-way collision

The letter was shared by the Congress during its Sunday press briefing on the Coromandel Express accident. "Why did Railways IGNORE this letter warning of a system failure where a crash between a passenger & goods train caused by interlocking failure could've led to loss of lives?" Trinamool spokesperson Saket Gokhale said.

What happened with Sampark Kranti in February

Going by the internal letter now available in the public, On February 8, the Sampark Kranti Express encountered a 'veru serious unusual incident' at Hosadurga Road station in Karnataka. The train's point was set to down main line where a goods train was there. The driver was alert and stopped the train averting a major disaster, the note read.

After the Coromandel crash, the Sampark Kranti event does not strike as unusual as opposition leaders point out that the same thing happened with the Coromandel -- there was a 'signalling intervention'

'Serious flaws in the system'

The Sampark Kranti incident indicates that there are serious flaws in the system where the route of despatch gets altered after a train starts on signals with correct appearance of route in the Signal Maintainer's panel, the railway official noted. "This contravenes the essence and basic principles of interlocking," the railway official noted.