After the deadliest rail accident in India in decades, the country is racing to deploy an automatic train protection system called Kavach across its vast network. Here is what it is, how it works, and what is at stake.
On the evening of 2 June 2023, three trains converged on a single stretch of track near Bahanaga Baazar station in Odisha. The Coromandel Express, running from Shalimar to Chennai, collided at speed with a stationary goods train that had been directed onto the wrong line by a signalling error. Within seconds, the derailed coaches lay across the adjacent track. Then the Yesvantpur-Howrah Express arrived.
The death toll eventually reached 296. More than 1,200 people were injured. It was the deadliest railway accident in India in over two decades — and it triggered a reckoning that is still unfolding today.
What is Kavach?
Kavach — the Hindi word for 'armour' — is India's Automatic Train Protection (ATP) system. Developed by RDSO, the Research Designs and Standards Organisation based in Lucknow, and co-developed with three Indian private firms, it sits in the same category as the European Train Control System (ETCS) and Japan's ATC (Automatic Train Control) — systems that override driver action when a collision is imminent.
The system works through continuous radio communication. Every equipped locomotive carries a Kavach unit that talks in real time to track-side units (RFIDs and radio towers) and to other Kavach-equipped locomotives ahead on the same line. The moment the system calculates that a collision or a dangerous signal violation is about to occur, it applies the brakes automatically — without waiting for the driver to react.
The most critical function is preventing what railway engineers call a SPAD: Signal Passed at Danger. A driver who misses a red signal — through fatigue, distraction, or a visibility problem in heavy rain or fog — will have the brakes applied automatically. The system also prevents a second train from entering a block section where another train is already present.
Kavach has been tested at closing speeds of up to 160 km/h. It is certified to SIL4 — Safety Integrity Level 4 — the highest certification in the IEC 62278 railway safety standard, meaning failure is permitted only once every 100,000 years of continuous operation.
The Odisha accident and the acceleration that followed
Investigators concluded that the Balasore accident was caused by a signalling configuration error — a points and signal setting that sent the Coromandel Express onto an occupied loop line. A properly functioning Kavach system, had it been installed on that stretch of track, would have detected the approaching freight train and automatically slowed or stopped the Coromandel Express before impact.
Before Balasore, Kavach had been deployed on approximately 1,465 kilometres of South Central Railway track — useful, but a fraction of the Indian Railways network of 67,000 route kilometres. The accident changed the pace.
Union Minister Ashwini Vaishnaw publicly committed to accelerating the rollout. The Union Budget 2023-24 allocated ₹1,112 crore for Kavach; the 2024-25 budget raised this to approximately ₹1,500 crore. The target is to cover the Golden Quadrilateral — the 6,000-kilometre network of tracks connecting Delhi, Mumbai, Chennai, and Kolkata — along with other high-density routes, as a priority.
The full network rollout, covering all of Indian Railways, is estimated to cost around ₹50,000 crore (approximately $6 billion) over several years — a major national infrastructure commitment, larger than the early budgets of many metro systems.
Why it is harder than it sounds
Deploying Kavach on 67,000 kilometres of track is not simply a matter of installing new software. Every locomotive on the route must be fitted, every signal post must be equipped with track-side units, every section must be tested and commissioned before passengers travel on it. Indian Railways runs approximately 13,000 trains per day; keeping services running while retrofitting the network requires surgical planning.
There are also supply-chain challenges. The equipment is largely manufactured domestically — part of the Make in India push — but scaling production from hundreds of units per year to tens of thousands requires new manufacturing capacity. Firms like Medha Servo Drives and Kernex Microsystems, which hold the Kavach licences, have been expanding, but they are building something that didn't exist at meaningful scale even five years ago.
The Bengaluru angle
South Western Railway (SWR), which operates mainline trains through Bengaluru and connects KSR Bengaluru City station, Yesvantpur, and Krishnarajapuram to the national network, is one of the zones included in the early Kavach expansion. Long-distance passengers who arrive at KSR and connect to Namma Metro's Purple Line effectively benefit from the system at both ends of their journey — the metro with its own built-in ATP, and the mainline train increasingly protected by Kavach.
Metro systems like Namma Metro already run fully automatic train protection as standard — no metro in India's modern fleet operates without ATP. But the integration of Kavach into the mainline network that feeds Bengaluru's stations closes one of the larger gaps in India's rail safety architecture.
The longer arc is more ambitious: once Kavach is fully deployed, a collision like Balasore becomes a system-level impossibility rather than a human-factor risk. That is the promise of the armour. Whether Indian Railways can forge it across all 67,000 kilometres in the time and budget available is the challenge that will define the next decade of Indian rail safety.