In the Kavach system (the Indian Railway's indigenous Automatic Train Protection system), the full form of RFID is Radio Frequency Identification.
Within this system, RFID is a crucial trackside component that acts as the "eyes" of the train, allowing it to know exactly where it is on the vast rail network.
How RFID Works in Kavach
The Hardware: Passive RFID tags are fastened to the track sleepers at predetermined intervals. Because they are "passive," they don't need a battery; they are powered by the signal from the train's reader.
The Reader: Every Kavach-equipped locomotive has an RFID Reader fitted underneath.
The Data Exchange: As the train passes over a tag, the reader scans it to retrieve pre-programmed data, including:
A unique Track Identification Number (TIN).
The precise location (distance from the station).
Information about the track (e.g., whether it's a main line or a loop line).
Why it's Critical
RFID solves a major problem: GPS isn't always reliable inside tunnels or under heavy cover. By using physical RFID tags on the tracks, the Kavach system gets an absolute, fail-safe location update. If the onboard computer sees that the train is approaching a "Red" signal at too high a speed based on its RFID position, it can automatically apply the brakes to prevent a collision.