Kavach Train Collision Avoidance System (TCAS)

Overshoot and Importance of the KAVACH System

Context (TH | TH | IE): The Vizianagaram train accident may have occurred due to overshot.
The anti-collision KAVACH system is not available on either of these trains.

Overshot is technically called Signal Passing at Danger (SPAD).
It occurs when a train doesn’t stop at a red signal and keeps moving forward.
It is a serious safety hazard that can lead to train collisions and other accidents.

Human error: Due to fatigue, distraction, or signal misinterpretation.
Technical failure: It includes problems with the train’s brakes, signalling system, or track.
External factors: Such as bad weather or obstructions on the track.

The KAVACH is an indigenously developed Automatic Train Protection (ATP) system.
It was developed by the Research Design & Standards Organisation (RDSO) of the Indian Railways.
It has been adopted as the National ATP System for Indian Railways.
It is a state-of-the-art electronic system developed under the Atmanirbhar Bharat initiative.
It is one of the cheapest systems with Safety Integrity Level-4 (SIL-4) certification.

Under SIL-4, the probability of error is 1 in 10,000 years.

Avoid SPAD: When a red signal is ignored, and two trains approach each other on the same track, the system applies sudden brakes.
Overspeed protection: It will automatically apply the brakes if the train exceeds the speed limit.
Collision avoidance: Through direct loco-to-loco communication.
Signal information: The system offers the driver real-time signal information. It provides a line-side signal display in the cabin for better visibility in fog and at high speeds.
Automatic whistling at level crossings: A big boon during fog conditions.
SOS feature: To control trains in emergency situations.

The South Central Railway (SCR) Zone pioneered implementing the KAVACH.
Trials of Kavach were conducted on the Lingampally–Vikarabad–Wadi and Vikarabad–Bidar sections of the South Central Railway, covering a distance of 250 km.