DNA Explainer: What is electronic interlocking system, 'root cause' behind the Odisha train tragedy?

The root cause behind the Odisha triple train accident is said to be its much-hyped electronic interlocking system. 

The commissioner of railway safety has investigated the matter and Railway Minister Ashwini Vaishnaw said, "The commissioner of railway safety has investigated the matter and let the investigation report come but we have identified the cause of the incident and the people responsible for it... It happened due to a change in electronic interlocking. Right now our focus is on restoration."

Electronic interlocking system explained

Interlocking is a part of railway signalling which are controlled in a manner to ensure safe passage of train through controlled areas. Electronic Interlocking (EI) is a type of signalling.

Any modification is easy in the EI system as the interlocking logic is based on software. The EI System is a processor-based system which has extensive diagnostic tests built into it.

Read: Odisha train accident: Electric interlocking, faulty signaling machine real reason behind tragic train crash

Malfunction of the EI system

Generally, the signal becomes red in case of a malfunction in the system. The issue could be caused by external interference, such as human error, malfunction, etc. 

As per India Today's report quoting a source, In the case of the Odisha railway accident, some construction work in the area was taking place and it is possible that the point was set on the loop line instead of the normal line. 

According to railway experts, if there is some construction going on, it is possible that the cable wires get cut. It can be a short circuit also. It is a fail-safe system. The signal turns red if there is a problem.