Kavach is an automatic train protection (ATP) system developed by the Indian Railways through Research Designs & Standards Organisation (RDSO). It is a safety integrity level 4 (SIL-4) certified technology.
The system can alert the loco pilot and take control of the brakes and bring train movement to a halt automatically when it notices another train on the same line within a prescribed distance. The device continuously monitors train movement and sends signals ahead to the locomotives, which is helpful during adverse weather conditions such as fog.