Tunnel Communication Systems in Indian Railways

Indian Railway tunnels are classified into three categories based on length: less than 500 meters, 500 meters to 5 km, and more than 5 km.

A radio communication system used in Indian Railway tunnels for train operation, maintenance, and emergencies, operating in the 146-163MHz range.

A radio system for train operations in Indian Railways, utilizing frequency bands of 424-430MHz.

Mobile communication systems for Indian Railways, using GSM-R frequencies (876-915 MHz/921-960 MHz uplink/downlink) and recommending LTE in the 700MHz band.

A communication system operational on Indian Railways using frequency bands 405-512 MHz.

A radio communication system for Indian Railways in the 370-430MHz range, providing communication with headquarters and train personnel.

A system of radio communication used in tunnels of varied lengths, covering maintenance, driver/guard communication, and emergency situations.

Communication between radios located in different tunnels of the same railway network.

Converts RF signals to light signals, used in tunnels longer than 500 meters, connects to optical remote units.

Converts optical signals to RF signals, transmits wireless signals via leaky cable to cover tunnels longer than 500 meters.

Used in tunnels shorter than 500 meters, amplifies and rebroadcasts radio signals via dual radiating cable systems, covering VHF Simplex, LocoTrol, GSM-R/LTE, TETRA and TCAS.

Flame-retardant cable used for wireless communication within tunnels, enabling signals to leak out and cover the tunnel space preventing smoke accumulation.

Reliable wireless communication system for railway tunnels, featuring continuous coverage with no interference, especially important in harsh environments.

Requires Master Unit and Optical Remote Unit for wireless signal coverage.

Uses Off-Air Channelized Repeaters for wireless signal coverage.

Flame retardant, low smoke, zero halogen cable specifically for tunnels, ensures safety in case of fire.

A socket for emergency communication in tunnels.

Regular inspections of all tunnel communication systems.

Daily report of communication system failures to managing officer.

A summary of communication system failures for the month submitted to HQ.

Essential tools like optical meters for maintaining communication equipment in the tunnel.

Sound hoods are recommended for noise reduction to improve conversation quality.

Emergency telephones should connect to the existing emergency control system, ending at the Divisional Control Room.

A PA system, with speakers every 100m, offers announcements for staff and instructions during incidents, in tunnels longer than 500m.

Hotline telephone services extend to tunnel maintenance boxes, connected to central/ divisional control rooms for fast communication.

An IP-based video surveillance system with cameras providing coverage throughout tunnels, to be monitored at the control center.

Monthly checks of transmitting frequency and power, usually measured internally through a connected PC/Laptop to the Master Unit.

Inspecting input and output voltage/current and specific gravity of each cell in the supply system weekly for maintenance.

Antenna systems, cables, and connectors are inspected weekly for any damage or breakdowns at Master location and inside tunnel locations

A type of RF coaxial cable with gaps in its outer conductor, allowing radio signals to leak in/out along its length, acting like an antenna.

Antennas for VHF Simplex, LocoTrol, GSM-R/LTE, TCAS, TETRA systems should be installed at the tunnel site.

Antennas for VHF Simplex, LocoTrol, GSM-R/LTE, TCAS, TETRA systems located on a tower above the tunnel.

A device used to connect fiber optic cables in tunnels longer than 500 meters.

Power supply with battery backup (230VAC 50Hz or -48VDC) needed for master units, optical remote units/repeaters in tunnels.

Emergency telephones should be installed at key tunnel points like cross passages, walkways, and every 250 meters; to account for noise and poor light.

A ring of optic fiber and copper cable connecting PA systems and CCTV cameras.

Communication infrastructure in tunnels is tailored for different lengths (under 500 m, 500m to 5 km, over 5 km) in accordance with the specific requirements.

Uses off-air repeaters for radio communication within shorter tunnels.

Requires master units and optical remote units for radio signals in longer tunnels.

A radio system (146-163MHz) for essential train operations and emergencies in tunnels.

A train radio system (424-430 MHz) for train operations in Indian Railways.

Mobile communication system (876-915 MHz/921-960 MHz and 700 MHz) for railway operations, including tunnels.

A radio communication system (405-512 MHz), for other railway operations and in tunnels.

A radio system (370-430 MHz) for communication with headquarters and tunnel operators.

Flame-retardant cable in tunnels that allows signals to leak, covering the space.

Converts RF signals to light signals, crucial for tunnel communication exceeding 500 meters, connecting optical remote units.

Converts light signals (optical) back to radio waves (RF), broadcasting signals via leaky cable for tunnel communication (over 500 meters).

Amplifies and rebroadcasts radio signals for tunnels under 500 meters, using dual radiating cables.

Flame-retardant cable allowing radio signals to leak out/in, ideal for wireless communication inside tunnels.

Requires Master Unit and Optical Remote Unit for wireless coverage – a more extensive communication system.

Employs Off-Air Channelized Repeaters, a more economical communication solution.

A flame-retardant, low-smoke, zero-halogen leaky cable crucial for minimizing smoke accumulation.

A continuous reliable wireless system crucial for railway tunnels, ensuring clear audio, and seamless operation in harsh tunnel environments.

Sockets for emergency communication in tunnels.

Regular inspections of tunnel communication systems.

Daily report of communication system failures to a controlling officer.

Summary of communication failures reported to headquarters monthly.

Essential tools for maintaining tunnel communication equipment.

A type of RF coaxial cable with gaps in the outer conductor, allowing radio signals to leak in or out along its length, functioning as an extended antenna.

Tunnel communication systems for tunnels shorter than 500 meters that use off-air repeaters.

Tunnels longer than 500 meters require master units and optical remote units for wireless signal coverage.

A device used to connect fiber optic cables, specifically in tunnels longer than 500 meters.

Telephones installed at key points in tunnels, including cross passages and walkways, ensuring smooth communication even during emergencies with high noise and poor light conditions. Telephones should be placed every 250 meters.

A ring of optic fibre and copper cable connecting various facilities like PA systems and CCTV cameras within the tunnel.

Antennas for VHF Simplex, LocoTrol, GSM-R/LTE, TCAS, and TETRA systems are located at the tunnel site for tunnels less than 500 meters.

Antennas for VHF Simplex, LocoTrol, GSM-R/LTE, TCAS, and TETRA systems are installed on a Tower above the tunnel for tunnels longer than 500 meters.

Emergency telephones connect to the existing emergency control system, terminating at the Divisional Control Room.

A system with loudspeakers, spaced every 100 meters in tunnels, to provide announcements and warnings to tunnel staff and general public in unusual situations.

Extends telephone services to tunnel maintenance boxes, connecting them to central or divisional control rooms for quick communication.

IP-based cameras provide coverage of tunnels, transmitting footage to a control center for monitoring.

Checks of the transmitting frequency and power of the tunnel communication system, often done by the system itself and checked using a PC/laptop.

Inspecting input/output voltage, current, and battery cell condition for the tunnel communication system's power source.

A weekly inspection of antenna systems (especially at the master location) and all leaky cables to ensure no damage or breakdowns.

Checking the master unit for any fault alarms weekly. If any faults exist, use Laptop/PC diagnostics to pinpoint the issue.