Kavach version four has been commissioned on 1,452 route km, covering the high density Delhi–Mumbai and Delhi–Howrah corridors. The rollout included laying 8,570 km of optical fibre, installation of 1,100 telecom towers, deployment of trackside equipment over 6,776 RKm and establishment of 767 station data centres. Trackside implementation has been taken up on 24,427 RKm covering Golden Quadrilateral, Golden Diagonal and High Density Network sections. The programme aims to strengthen signalling and train protection on key routes.Kavach is an indigenously developed automatic train protection system certified to safety integrity level four. The system intervenes to apply brakes automatically if a loco pilot fails to adhere to speed restrictions and improves safety in adverse weather and complex yards. Field trials began in February 2016 and the system was adopted as the national ATP in July 2020 after independent safety assessment. Version four of the specification was approved in July 2024 with enhanced location accuracy and interfaces to electronic interlocking.Deployment includes provision of Kavach on 4,154 locomotives and work to equip 8,979 locomotives and 1,200 EMU and MEMU units. More than 55,000 technicians and engineers have been trained, including about 47,500 loco pilots and assistant loco pilots. The cost for trackside and station equipment is approximately Rs. 5 million (mn) per km and the cost for locomotive equipment is approximately Rs. 8 mn per loco. Funds utilised up to February 2026 total Rs. 27,639 mn, equivalent to Rs. 27.639 bn.Safety spending has risen from Rs. 392,000 mn or Rs. 392 bn in 2013–14 to Rs. 1,203,890 mn or Rs. 1,203.89 bn in 2026–27, supporting technology upgrades. Consequential train accidents have fallen from 135 in 2014–15 to 14 in 2025–26, a reduction of 90 per cent, and the consequential accident index has declined from 0.11 to 0.03, or 73 per cent. Electrical interlocking, level crossing interlocking and track circuiting have been extended to reduce human error and verify track occupancy. The ministry reported in a parliamentary reply to the Lok Sabha.