Train Collision Avoidance System is widely known as TCAS is meant to provide mainly:

• Movement authority with display of signal aspect in Loco;
• Preventing trains to pass signal at danger;
• Speed supervision.

TCAS shall consist of On-board, Station, Trackside & On-track equipments. A UHF full-duplex radio communication unit with hot stand-by along with its antenna equipped in each Loco to communicate with other TCAS units. A UHF full-duplex radio communication unit with hot stand-by along with its antenna equipped in Station to communicate with Loco TCAS units. RFID tags shall be fitted on point zones, near Signals & track in block section for giving Track Identification Number (TIN) information to loco TCAS, location correction, identifying signal by Loco TCAS & for direction determination in tunnels.

For goods trains, more locomotives are required to haul goods trains on the track with steep gradients. Due to limitation of coupler capacity, all the locomotives cannot be attached in front of the train. For such heavy haul operation on steep gradients, normally three or more locomotives are utilized in consist placed at the front, middle and rear of the train. A remote system "LocoTrol" for controlling locomotives placed in the train consist from the leading locomotive through a wireless link is, therefore, required.

Simultaneous repetition & execution of commands, given by “Lead” locomotive to “Remote” locomotive by a wireless link, such as traction, air/vacuum braking, dynamic braking or any other functions performed by the driver of the lead unit and duplicated (transmitted) in “Remote” units.

In some special scenarios, construction, hill or mountains will block the communication, especially in tunnels. To solve the communication between Loco and Station/IBS equipment, communication between Loco equipments, HELIOS^® Critical Communication Off-Air Repeaters or Digital Optical Transport System is designed to extend the coverage of Railways Radio into Tunnels sections and Trackside areas blind to BTS coverage.

HELIOS^® Digital Dual Band Repeater is a carrier-grade, consumer-friendly digital smart booster that maximizes a subscriber’s indoor wireless experience by eliminating in-building dead zones. It is really cost-effective and intelligent solution to solve the last mile coverage problem, which is adopting SDR (Software Define Radio) technology basis on FPGA & DSP (Digital Signal Processing) platform. It enables on-the-fly filter be changed / upgraded by software without expensive hardware upgrading.