Solutions · Railways and metros
Inside a tunnel, trains lose radio communications. We bring radio coverage to every point of the tunnel.
We design, install, and maintain radio coverage systems for railway and metro tunnels: multiband DAS systems, radiating-cable continuity monitoring, and microwave links to connect remote sites, backed by more than twenty years of experience in mission-critical communications.
The three challenges of running a railway line.
What a railway operator has to guarantee every day, in the tunnel and along the line.
Continuous coverage inside the tunnel
Operational radio networks, emergency networks, and cellular coverage for passengers all have to stay live along the full length of the tunnel. A short circuit caused by a fire, or an open line from a faulty connector, can cut communications exactly where there is no alternative.
Multiple technologies on one system
Different radio technologies have to coexist on the same in-tunnel infrastructure: TETRA, DMR, VHF/UHF, and multiband cellular coverage. This calls for radiating cable and DAS systems that carry them all, without multiplying the installations.
A long-lasting investment
The system has to last for years and be maintained without stopping train traffic: what matters is component quality, technical documentation, and scheduled overnight work.
How a coverage system in a railway tunnel is built.
The cross-section of a tunnel section: the signals of the radio networks arrive at the technical room at the portal, the DAS unit combines them onto a single radiating cable, and a microwave radio link carries the communications to the control room.
- Incoming radio services
- The signals of the operations network, the emergency services network, and cellular coverage for passengers arrive separately at the technical room at the portal.
- DAS unit and radiating cable
- The master unit combines the three signals onto a single radiating cable run along the bore. The remote unit, in the technical room at the opposite portal, feeds the same line from the other end.
- Technical rooms at the portals
- At the two tunnel portals, the technical rooms house the radio equipment, the DAS units, and the power distribution boards.
- Microwave radio link
- Where optical fiber does not reach, the microwave link carries the communications from the technical room to the control room.
One distribution system, three radio services.
Inside the same tunnel, operational communications, emergency communications, and cellular coverage for passengers all have to coexist. A single radiating cable, laid along the bore, distributes all three services.
Operations network
The operations network is the one station staff, train drivers, and maintenance crews use to talk to each other and to the control room. We design and build these networks in DMR, TETRA trunking, and VHF/UHF technology, and maintain them over the years.
Emergency services network
The fire service, emergency medical services, and law enforcement enter the tunnel with their own radios and have to keep talking to their own control rooms. We distribute the signals of their networks on the same installation, without building a second infrastructure.
Cellular coverage
Passengers expect to be able to make calls and browse the internet inside the tunnel too. We distribute the mobile operators’ bands over the same line and, with TP-CELLX, continuously verify that the 2G, 3G, and 4G signal is present along every stretch.
What a system for a railway or metro line includes.
The systems we build and verify in the tunnel, in the stations, and along the line.
Radiating cable in the bore
- Radiating cable laid along the sidewall, at the height and distance from the wall set by the design
- Brackets at a constant spacing, respecting the minimum bending radius
- Joints, connectors, and termination loads fitted and sealed against moisture
- Couplers, splitters, and line amplifiers housed in the wall niches
- Antennas at the portals and in the cross passages between bores, where the radiating cable does not reach
Multiband DAS
- Master unit in the technical room at the portal and remote units distributed along the tunnel
- Optical fiber link between the master unit and the remote units
- Filters, amplifiers, and attenuators dedicated to each service band
- Injection points for the mobile operators’ signals
- Power split between the sections, calculated from the coverage study
Coverage in the stations and above ground
- Distributed antennas in the underpasses, on the platforms, and in the station concourses
- Amplifiers and repeaters for the underground rooms, the depots, and the workshops
- Site antennas and repeaters along the open-air sections and in the station yards
- Verification of signal continuity in the transition between the station and the tunnel
- Coverage tests on board the train and with the staff’s portable terminals
Control room and dispatch
- Dispatch consoles and operator positions running the Respondr platform
- Recording of every channel, searchable by radio ID, time, channel, and talkgroup
- Gateways to the analog, digital, and IP radio networks already in service
- Audio routing between adjacent positions, with echo cancellation
- Operator profiles, access control, and integration with the corporate authentication system
Links between the sites
- Point-to-point and point-to-multipoint microwave links to the sites that optical fiber does not reach
- Optical fiber backbones between the technical rooms at the portals and the control room
- Network equipment, PoE power supplies, and patch cabinets
- Redundant link paths, so that an outage on one section does not isolate the tunnel
Power supply and earthing
- Distribution boards, protection devices, and lines dedicated to the radio equipment
- Power supplies, uninterruptible power supplies, and buffer batteries sized for the required autonomy
- Power supply for the remote units and the amplifiers installed along the bore
- Bonding of equipment, racks, and antenna supports to the earthing system
- Surge arresters on the RF lines and on the power lines
System monitoring
- TP-CCV2 in the base station cabinet: radiating cable continuity, short circuits, and open lines
- TP-RFX in the tunnel: radio carriers from 15 MHz to 2.7 GHz, including TETRA and DMR
- TP-CELLX in the tunnel: 2G, 3G, and 4G coverage for every mobile operator
- Track-TP: the status and alarms of every device on a single dashboard, with notifications by email, WhatsApp, and Telegram
- SNMP traps and relay contacts to the railway operator’s supervision systems
Technical rooms at the portals and shelters
- Racks, cabinets, and cable routes in the technical rooms at the tunnel portals
- Air conditioning, ventilation, and filters
- Temperature and humidity sensors, environmental alarms
- Labeling of equipment, cables, and connectors according to the design drawings
- Access control, lighting, and physical security of the room
What happens when radio coverage degrades inside a tunnel.
A concrete case: from detecting the problem to centralized supervision, without ever leaving the tunnel without communications.
Coverage reaches into the tunnel
In a railway tunnel, the radio signal from outside does not get in. We design and install multiband DAS and radiating-cable systems that carry operational radio networks, emergency networks, and cellular coverage inside, on a single line.
Radiating-cable continuity stays under control
The radiating cable is the backbone of in-tunnel coverage. TP-CCV2, a patented Teleproject system, monitors the continuity of the line and reports a short circuit or an open line in real time, before the tunnel is left without communications.
The cellular signal is checked continuously
TP-CELLX, installed in the tunnel, continuously checks 2G, 3G, and 4G cellular coverage for every operator. When it detects a loss of signal, it logs the fault and raises an alert: in that stretch, passengers can no longer make calls.
Radio carriers stay monitored
TP-RFX monitors in-tunnel radio carriers from 15 MHz to 2.7 GHz, including TETRA and DMR: it detects signal degradation before it becomes a service outage.
Everything converges into supervision
Alarms from TP-CELLX, TP-RFX, and TP-CCV2 converge on the Track-TP platform: from a single dashboard, the operator sees the status of coverage and equipment along the whole line, with real-time notifications.
The systems we field.
Each solution has its own in-depth page: here you will find only what it does for a railway or metro line.
- In-tunnel coverage
DAS and radiating cable
We design and install multiband DAS and radiating-cable systems in railway and metro tunnels, with TETRA, DMR, VHF/UHF, and cellular on the same line.
- Radiating-cable continuity
TP-CCV2
A patented Teleproject system that reports short circuits and open lines on the radiating cable in real time, before the tunnel is left without radio coverage.
- Cellular coverage
TP-CELLX
Continuously monitors cellular coverage in railway tunnels and alerts the control room when the operators’ signal drops.
- Spectrum monitoring
TP-RFX
An outdoor spectrum analyzer that monitors TETRA and DMR carriers and other in-tunnel radio transmissions, from 15 MHz to 2.7 GHz.
- Supervision
Track-TP
A web platform that brings together, on a single dashboard, the status of network devices, radio networks, and sensors along the line, with real-time alarms.
- Operational communications
DMR and TETRA radio networks
We design and build operational radio networks: DMR systems, TETRA trunking, and VHF/UHF links, from design to maintenance.
- Site-to-site links
Microwave links
Point-to-point and point-to-multipoint microwave links to connect radio sites and control rooms where fiber does not reach.
- Control room
Radio rooms and dispatch
We build radio rooms with Funktronic consoles and the Respondr platform: operational and emergency radio networks at a single operator position.
- Before the tender
Radio coverage study
Propagation models, link budgets, and system sizing: the technical documentation you need to design coverage and present the project in a public tender.
Learn more.
TechnicalGSM-R and FRMCS: the railway radio network explained
How GSM-R works, which frequencies it uses and what changes with FRMCS: the railway radio network behind ETCS, from 876–880 MHz to 5G migration from 2030.
MonitoringHow to Monitor the GSM-R Network
How to monitor GSM-R railway communications networks: EIRENE coverage requirements, handover management, the TP-CELLX solution, and the transition toward FRMCS.
Frequently asked questions.
The questions we are asked most often about this type of system.
If the radio technology changes, can the radiating cable already laid in the tunnel be reused?
In most cases yes. The radiating cable and the passive components (couplers, splitters, connectors) work over a wide frequency range, so what changes is the equipment at the head of the line and the band filters, not the line laid along the bore. Reuse still has to be verified on the new band: as the frequency rises the cable attenuation increases, and the same line may need more amplifiers or shorter sections between feed points. The check is done before the decision, by measuring attenuation and standing wave ratio (SWR) on the existing line and reviewing the frequency range declared for the components already installed.
In a metro, is the system different from the one in a railway tunnel?
The principle is the same: a distribution line, radiating cable or DAS, carries several radio services into an enclosed environment the outside signal cannot reach. What changes is the context around the tunnel. In a metro the concourses, underpasses, and platforms have to be covered as well, the technical rooms are closer together, and passenger service only stops at night, so the work is concentrated in the hours when the line is closed. The number of access points to the tunnel also changes, and that determines how long the cable laying takes.
Does radio coverage in the tunnel keep working during a power failure?
Yes, if the system was sized for it. The radio equipment, the DAS units, and the amplifiers installed along the bore are powered by uninterruptible power supplies and buffer batteries, sized for the autonomy the operator requires: autonomy is a design figure, not a property of the equipment, and it has to be stated in the specification. At acceptance the check is done in the field, by removing the mains supply and verifying that communications stay up for the required time.
What do you need in order to put radio coverage for a railway tunnel out to tender?
Two things: the list of radio services that have to reach inside the tunnel, with the level of continuity required for each, and a radio coverage study that turns those requirements into systems. The study produces the propagation models, the link budget, and the equipment sizing — the technical annexes the specification is built on, and the reason bids become comparable. It is also worth stating in the tender notice the conditions of access to the tunnel, meaning which traffic interruptions will be granted and in which time slots, because these determine the duration of the works and the price of the labor.
Our systems integrate with the equipment you already have.
No closed systems: we use open protocols, let different technologies coexist on the same installations, and work with the certifications public tenders require.
Multi-protocol on the same cable
TETRA, DMR, and VHF/UHF coexist on the same radiating cable alongside multiband cellular coverage: existing installations stay valid even when the radio technology changes.
Integration with the operator’s systems
The monitoring systems interface with the railway operator’s supervision platforms via SNMP, relay contacts, and APIs: alarms arrive where you already work.
Certifications and qualifications
Teleproject is certified to ISO 9001:2015 and qualified under SOA OS 19. The Respondr and Track-TP platforms are designed in compliance with the NIS2 directive and the ISA/IEC 62443-3-3 standard.
Request a proposal for your railway line.
Feasibility analysis, radio coverage study, and project planning, tailored to your requirements.