Medha’s Train Collision Avoidance System (TCAS) is an advanced, cost-effective SIL-4 certified solution designed to ensure the safety of both passengers and railway assets. The TCAS system minimizes the risk of human error by providing automated control and protection, preventing potential collisions and catastrophic accidents.

TCAS is applied on mainline railways, freight lines, and long-distance trains.

System Overview

Medha’s TCAS consists of two main components: Wayside TCAS and Vehicle Onboard TCAS.

Wayside TCAS

1. Comprises a network of control units, radio units, and passive RFID tags placed at key locations within the station and along the block sections.
2. The RFID tags provide critical information about the train’s location, which is transmitted to the Loco TCAS through a secure radio link.

Onboard TCAS

1. An onboard system that includes a control unit, speed sensor, RFID reader, radio unit, and display panel.
2. The RFID reader, mounted under the locomotive, detects RFID tags placed between the rails and collects data such as the unique tag ID, direction of travel, and track identification number (TIN).
3. This data is communicated to the Station TCAS, which then provides vital information to the locomotive, including signal aspects and distance to approaching signals.

How It Works

1. The Onboard TCAS receives data from the Wayside TCAS, including signal aspects, movement authority (MA), and track conditions.
2. It continuously monitors the train’s speed using sensors mounted on the locomotive axle.
3. If the train exceeds safe speed limits, an audible alert is sounded for 5 seconds. If the speed is not corrected, the system automatically initiates emergency braking, bringing the train to a complete stop.

Fail-Safe Features

1. Two-out-of-Two Architecture: Ensures fail-safe operation for onboard units.
2. Redundant Design: The Wayside TCAS uses a two-out-of-two architecture with a hot standby for enhanced reliability.
3. Full ATP Functionality: Provides comprehensive Automatic Train Protection (ATP) to prevent collisions.
4. Enhanced Safety: The Wayside TCAS can detect potential collision scenarios even if there are errors in the interlocking system.
5. Redundant Communication: Utilizes dual radios for reliable and continuous data transmission.

Medha’s TCAS offers a robust solution to enhance railway safety, minimizing the risk of collisions and providing reliable protection against human error.