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.

Utilizing a centralized digital CPRI distributed architecture, HELIOS^® Digital CPRI Optical Transport System is a two-tier architecture consisting of the Head-End Units and Optical Remote Units (ORUs).

Head-End Unit

Head-End Unit combines wireless Off-Air Repeaters and Digital Optical Master Unit in the same case with channelized filters support. Head-End Unit is IP67 waterproof cabinet and wireless coupled the outside air signal. On the forward path, the Head-End receives the RF signals and digitizes the designated RF bands and digitally transports them over single mode fiber to the Remote Units. On the reverse path, the Head-End receives the digitized RF signals from the Remote Unit and converts them back to RF.

Each Head-End has four 10Gbps SFP+ digital optic ports and supports up to 32 ORUs by star, chain, ring and hybrid network topologies. The Head-End utilizes an embedded WEB management system for system configuration and network monitoring. The embedded WEB management system collects alarm information from both OMUs and ORUs.

Optical Remote Unit - ORU

Typical mounting options for the ORU include pole-mount, wall-mount. And the enclosure of the ORU is fully sealed IP67 rated compact design, which minimizes maintenance and is ideal for harsh environments.

On the forward path, the ORU receives the digitized spectrum from the Head-End Unit and converts the spectrum back into RF to be distributed via an externally mounted antenna system. On the reverse path, the ORU digitizes the designated RF spectrum and digitally transport it over single-mode fiber to the Head-End.