Indian Railways has commissioned Kavach Version 4.0 for the first time on South Central Railway (SCR), beginning the next phase of deployment of the indigenous Automatic Train Protection (ATP) system. The upgraded system is operational across 108 route kilometres on the Malkajgiri–Kamareddi section of the Hyderabad Division.

The deployment replaces Kavach Version 3.2 on the section and follows the installation of the earlier version across 1,465 route kilometres on SCR. Indian Railways said Version 4.0 incorporates technological upgrades intended to improve safety, reliability and train operations, with wider deployment planned across the national network.

The latest version provides greater location accuracy, allowing more precise train positioning, and offers improved information on signal aspects in larger yards. It also supports a station-to-station Kavach interface through Optical Fibre Cable (OFC), strengthening communication and system integration. Direct interfacing with existing Electronic Interlocking Systems is intended to improve coordination with signalling infrastructure.

Kavach was developed by the Research Designs & Standards Organisation (RDSO) in collaboration with Indian industry. The Safety Integrity Level 4 (SIL-4) certified system is designed to prevent trains from passing red signals and to apply brakes automatically when a driver does not comply with speed restrictions.

The system can also help prevent collisions between Kavach-equipped locomotives, transmit emergency SOS messages and support centralised live monitoring of train movements. Unlike conventional signalling, which depends substantially on a loco pilot responding correctly to trackside signals, ATP continuously monitors train movement and can intervene when safety parameters are breached. The commissioning on SCR moves Version 4.0 beyond trials and limited deployment towards broader adoption across Indian Railways.