Indian Railways has commissioned Kavach 4.0, the latest version of its indigenous Automatic Train Protection (ATP) system, across 738 route kilometres on two major national corridors. The deployment covers 633 route kilometres in the Palwal–Mathura–Nagda section of the Delhi–Mumbai route and 105 route kilometres in the Howrah–Bardhaman section of the Delhi–Howrah route. The update was shared by Railway Minister Ashwini Vaishnaw in a written reply to the Rajya Sabha. Kavach is a safety-certified SIL-4 technology that assists loco pilots by automatically applying brakes when speed limits are exceeded and ensuring safe operations even in adverse weather. Field trials began in 2016, followed by independent safety assessments. Version 3.2 was approved for supply in 2018–19, and Kavach was adopted as India’s national ATP system in 2020. Implementing the system involves installing station and trackside equipment, RFID tags, telecom towers, optical fibre cable and onboard units for locomotives. Drawing on experience from deploying version 3.2 across 1,465 route kilometres in the South Central Railway zone, Indian Railways introduced several enhancements, leading to the approval of Kavach 4.0 in July 2024. The upgraded version offers improved location accuracy, enhanced relay of signal aspects in large yards, an OFC-based interface between stations and direct integration with electronic interlocking systems. These improvements support wider deployment across the national network. Extensive trials preceded commissioning on the two major corridors, and work is underway to equip the remaining sections of the Delhi–Mumbai and Delhi–Howrah routes. Indian Railways has reported substantial progress in establishing supporting infrastructure. Optical fibre cable has been laid along 7,129 km of track, 860 telecom towers have been installed, 549 stations have been fitted with Kavach, and trackside equipment has been deployed across 2,674 route kilometres. A total of 4,154 locomotives have also been equipped with onboard Kavach units. Trackside work is in progress along 15,512 route kilometres, covering the Golden Quadrilateral, Golden Diagonal, High Density Network and other identified routes. Bids have been issued for equipping an additional 9,069 locomotives with Kavach 4.0 as part of the phased rollout. Training for the system is being conducted at centralised railway institutes, with more than 40,000 personnel — including 30,000 loco pilots and assistant loco pilots — trained so far. Course development is being undertaken in collaboration with IRISET. The cost of installing trackside and station infrastructure is approximately Rs 5 million per kilometre, while fitting Kavach units on locomotives costs around Rs 8 million each. Expenditure on Kavach up to October 2025 stands at Rs 23.5436 billion, with an allocation of Rs 16.7319 billion for 2025–26. Funds are being released in line with project progress.