Train collision avoidance system, Kavach

In a bid to make rail travel safer, the Ministry of Railways has introduced an indigenously developed train collision avoidance system called Kavach, which automatically brings a train to a halt when it detects an obstacle on the track. Indian Railways plans to install Kavach across 2,000 rail route networks in 2022-23 and over 4,000-5,000 rail route networks every subsequent year.

Indian Railways plans to subsequently come out with tenders to deploy Kavach across the entire 68,446 km it operates.


  • It is indigenously built Automatic Train Protection System in development since 2012, under the name Train Collision Avoidance System (TCAS), which got rechristened to Kavach or “armour”.
  • It is a set of electronic devices and Radio Frequency Identification devices installed in locomotives, in the signaling system as well the tracks, that talk to each other using ultra high radio frequencies to control the brakes of trains and also alert drivers, all based on the logic programmed into them.
  • One of its features is that by continuously refreshing the movement information of a train, it is able to send out triggers when a loco pilot jumps signal, called Signal Passed at Danger (SPAD), a grave offense in railway operations with respect to safety, and the key to accidents like collision.
  • The devices also continuously relay the signals ahead to the locomotive, making it useful for loco pilots in low visibility, especially during dense fog.
  • Kavach was developed by the Research Design and Standards Organisation (RDSO) under Indian Railways in collaboration with private players.
  • The indigenously-developed anti-collision technology is SIL4 (Safety Integrity Level 4)-certified which means there is the probability of a single error in 10,000 years.
  • In the new avatar, India wants to position Kavach as an exportable system, a cheaper alternative to the European systems in vogue across the world.
  • While now Kavach uses Ultra High Frequency, work is on to make it compatible with 4G Long Term Evolution (LTE) technology and make the product for global markets. Work is on to make the system such that it can be compatible with other already installed systems globally.

It is considered as the world’s cheapest Automatic Train Protection System with the cost of rollout pegged at around Rs 30 lakh to 50 lakh per kilometer, a fourth of the cost of equivalent systems globally.