Odisha train accident: Here's all you need to know about Indian Railway's interlocking system

In the complex network of Indian Railways, recent incidents have sparked concerns regarding the bypassing of the vital signal interlocking system by electronic signal maintainers. The interlocking system, which ensures the safety and efficiency of train movements, is designed to prevent accidents and coordinate train operations seamlessly.

How it works

The sophisticated signal interlocking system, controlled and fixed by the cabin station master, integrates signals, switches (points), and track circuits to guide train movements and prevent accidents at junctions, stations, and signaling points. It acts as a

"fail-safe" mechanism, prioritizing safety by allowing signals to display a "proceed" indication only when the intended route is confirmed safe and clear. Even in the event of a failure, the system defaults to a red signal, signaling the locomotive pilots to halt the train, thus helping in avoiding a collision even in case of system failure.

Yellow signal for loop line

The interlocking system detects the occupancy and direction of trains, allowing signals to interlock and identify if the line ahead is occupied or unoccupied. Green signals indicate a clear track ahead for trains moving straight, while yellow signals signify the use of "loop lines" if they are unoccupied. The Yellow signal indicates that the train is going in the loop line.

At Bahanaga Bazar station, for example, an advanced electronic interlocking system is in place to ensure safe train operations. However, retired railway officials and recent incidents have shed light on the bypassing of the interlocking system during maintenance work. "In several incidences in recent past concerning the bypassing of inter locking system, signal maintainers were found responsible," said a retired official of Indian Railway adding that it has been noticed in some cases that they adopt shortcuts to avoid train delays, compromising the integrity of the safety mechanism.

According to sources train detentions are now being monitored department-wise to identify the causes of delays and discuss them during meetings. However, some maintainers, in an attempt to avoid train detentions, may resort to adopting shortcut methods. For instance, signal maintainers bypass the standard norms of the interlocking system to permit train movement during ongoing maintenance work.

When contact a senior officials, he said, "investigation is underway and everything will be clear once the report is clear."

Shortcuts a loophole area

"However measures are being taken to increase awareness among signal maintainers regarding the importance of following established procedures and not compromising on safety protocols. Additionally, stricter monitoring and disciplinary actions are being considered to deter any deviations from the prescribed norms" said a senior official on the condition of anonymity.