4T4R · 4×40 W
One default radio configuration: four transmit, four receive, 40 W per branch — sized for along-track sectors, MIMO for capacity, headroom for high-speed Doppler.
Default RU · both SKUsThe hardware
Fourteen boxes. Zero exotic parts.
The network is the product — so every box is deliberately commodity, rail-certified where it must be, and identical across railways. Two radio SKUs cover the world's FRMCS spectrum; everything else is the same hardware from Secunderabad to Stockholm.
The radio
Two bands. One radio family.
FRMCS spectrum worldwide converges on a short list. We build exactly two RU SKUs against it — no per-customer radio zoo. The DU, the core and every application are identical in both variants; only the RF front-end changes.
| Band | Range | Duplex | Where it's required | FRMCS.ai |
|---|---|---|---|---|
| n101 | 1900–1910 MHz | TDD | Europe — the UIC / ECC (20)02 RMR FRMCS band — and markets following it. The primary FRMCS band worldwide; capacity-leaning | SKU V1 — shipping design |
| n28 | 700 MHz | FDD (TDD-capable design) | India's railway 700 MHz allocation and other low-band markets. Reach-leaning: ~8–10 km rural sites, deep cutting and tunnel penetration | SKU V2 — shipping design |
| n100 | 900 MHz (RMR) | FDD | European GSM-R refarm band alongside n101 | Roadmap — same DU, core and apps; RU front-end only |
| NTN bands | L/S/Ka via partners | — | Satellite tier everywhere | Partner constellation terminals — not an RU (see orbital tier) |
A carve-out is enough
5–10 MHz of railway spectrum carries every FRMCS traffic class — voice, signalling and telemetry are small and deterministic. CCTV bulk rides satellite and station Wi-Fi offload.
QoS plan · 3GPP 5QI 65/69/82–85Open at the PHY
The O-DU speaks nFAPI (SCF 222/225) at the PHY boundary and the full O-RAN interface suite above it — pair our DU with any compliant L1/RU, or take the reference pairing.
O-RAN · SCF 222/225 nFAPI
The radio site
One cabinet, every corridor.
A tower site is a fixed bill of materials — identical for both band variants except the RU. Masts are standard 30 m lattice or existing structures; tunnels take leaky feeder or low-power repeaters fed from the portals.
Every site keeps its own time: GNSS-disciplined PTP with at least four hours of holdover, engineered per corridor for TDD phase discipline — not assumed.
- O-RU: 4T4R 4×40 W, n101 or n28 SKU.
- DU: 1U fanless x86 — Go control plane, C data path.
- Timing: GNSS + PTP grandmaster (G.8275.1), OCXO holdover ≥ 4 h.
- Transport: cell-site router, fibre preferred, microwave fallback, dual-homed where the line allows.
- Antennas: along-track two-lobe sector panels, 4-port MIMO.
- Power & housing: AC + 8 h battery (solar-hybrid option), IP55 cabinet, EN 50121-4 EMC, −33…+55 °C.
Compute — cloud to cabinet
Every function at the lowest tier that satisfies it. And no lower.
Vital transport terminates as close to the train as physics demands; learning and history live in the cloud where compute is cheap. That single placement rule shapes the whole estate.
Core cluster
3+ node x86 Kubernetes HA cluster, DPDK NICs for the UPF fast path, PostgreSQL + Valkey storage tiers, FIPS-class HSM pair for KMS/PKI roots, GPU pool for model training. Railway DC, sovereign cloud or hyperscaler — one GitOps release renders to all three.
H1 · control centre / cloudStation edge
One or two 1U nodes per station: local 5G breakout so ETCS and voice stay regional even if the WAN dies, oneM2M mid-tier, CCTV archive cache, passenger Wi-Fi offload. Loses the cloud, keeps the railway running.
H8 · stations & depotsThe moving edge
Every train carries its own compute: the TOBA gateway's NPU runs CCTV analytics, perception fusion and maintenance feature-extraction on board — features go up the radio, never raw video or waveforms.
H5 · on-train NPU- Dispatcher positions: hardened workstations with MCX console, PTT panel + headset, group/priority select, REC initiate and receive.
- Voice/data recorder: legal-grade REC and operational-voice recording, tamper-evident, policy-driven retention.
- Video wall: decode nodes for on-train and wayside CCTV streams.
- Incident desk: the Elastic Sky console — dock status, launch authorisation, incident-cell coverage, responder talkgroups.
- ATC boundary: redundant gateways hand EuroRadio (Subset-037 over IP) to the RBC, interlocking and TMS — which remain vendor-certified vital equipment.
Control centre
Two estates, one room.
Ours is the communication estate: every controller position is just another FRMCS user — same identity, same services — so a backup control centre is configuration, not construction.
The signalling vendor's estate — RBC, interlocking, traffic management — stays certified and untouched. We carry ATC. We never are ATC.
On the train
Rail-certified, cab to last coach.
Everything on board is EN 50155 territory — temperature, shock, vibration and fire-rated (EN 45545). The vital train-control kit (EVC, ATO, TCMS) stays vendor-certified; we present FRMCS transport at the UIC reference points.
| Unit | Specification |
|---|---|
| TOBA gateway | Fanless EN 50155 x86, dual PSU, −25…+70 °C; 2× band modems (tower/drone diversity) + NTN modem + passenger APN module; edge NPU; the UIC TOBA multipath session terminates here |
| Roof antenna set | Band MIMO ×2, NTN flat panel, GNSS — crash-rated radomes |
| Cab radio — on-board edge platform | The cab radio grown into an NVIDIA Jetson Orin edge computer — three jobs in one box: multi-bearer FRMCS gateway (5G primary · Wi-Fi 6/7 depot · Starlink remote, make-before-break failover), perception edge (camera + lidar + radar fused on the GPU), and LoRa IoT aggregation into oneM2M. Driver MCX terminal: PTT, group/priority select, guarded REC switch, DSD pedal tie-in |
| Crew panel | Guard / train-crew position: MCX client, PIS/PA control, door-dispatch comms, REC access |
| Perception head | Multi-modal forward camera head on the cab radio's Orin: high-speed global-shutter (~120 fps) + day/night WDR-IR + LWIR thermal, plus lidar and 77 GHz radar — TensorRT/DeepStream fusion; detections publish as FRMCS catalogue events with the right QoS |
| Bogie kit | Axlebox vibration/temperature nodes, per-car concentrator, gearbox oil sensor — bogie health at the source |
| Coach LAN | Per-coach Ethernet backbone, VLAN-segmented: vital / CCTV / PIS+PA / passenger Wi-Fi — never sharing the vital slice; Wi-Fi 6 APs, saloon + cab cameras, PIS displays and PA |
In people's hands
Every role, one identity model.
Drivers, guards, shunters, trackworkers, controllers — each is an FRMCS user with a device matched to the job. Same MCX services, same security, different form factor. The reference handheld is deliberately commodity; any 3GPP MCX-capable device with our client can substitute.
| Role | Primary device | What it carries | Form factor |
|---|---|---|---|
| Driver | Cab radio | REC, voice, safety-device (DSD), advisory display | Fixed in cab, guarded REC switch; handheld fallback off-train |
| Guard / crew | Crew panel + handheld | Voice, REC, PIS/PA control, door dispatch | Handheld follows the crew through the train |
| Shunter | Rugged handheld | Link-assured shunting groups, voice | Glove-usable, high-visibility, man-down |
| Trackworker | Handheld + wearable | Geofenced approach warning, lone-worker, voice | Wearable: GNSS + man-down IMU + haptic/audible alarm |
| Controller | Fixed OCC position | All voice/REC arbitration, incident console | Workstation-class |
| Incident commander | Incident kit | Emergency talkgroups, drone-cell status, video | Ruggedised case, pre-staged at dock stations and OCC |
| Maintenance | Tablet + handheld | TCMS/bogie dashboards, work orders, voice | Depot Wi-Fi + FRMCS dual-path |
Elastic Sky hardware
A cell site that fits on a trailer.
The disaster-recovery and rapid-deployment tier is two units: a dock station and a tethered drone. Docks are fixed at strategic points along the corridor, plus a road-trailer pool that can drive to any incident.
The dock's controller can execute a launch autonomously — the one site class designed to act even when the network around it is gone.
- Dock station: shelter, winch + tether management, charger, SBC controller, optional NTN backhaul for docks beyond tower coverage.
- Airframe: tethered multirotor, 80–120 m operating height, rain/wind envelope per certification.
- Payload: micro-RU with fronthaul over the tether, edge compute, perception pod (camera/radar/lidar).
- Tether: HV power up, fibre down — unlimited endurance, aircraft physically secured over railway land.
- Reserve power: on-board battery for controlled descent on tether loss.
Wayside IoT fleet
Cheap, battery-frugal, everywhere.
Beneath the 5G network sits the sensing fabric: ESP32-class nodes on LoRa and Wi-Fi HaLow, IP67, years on battery or solar — reporting to a Raspberry Pi-class station gateway. Nothing on this layer is vital; everything on it is replaceable in minutes with a screwdriver.
| Node family | Radio | Power | Measures |
|---|---|---|---|
| Track monitor | LoRa | Battery / solar | Vibration RMS · peak · dominant frequency, rail temperature, strain, tilt, train-pass events |
| Level crossing | LoRa | Line + battery | Barrier state, approach signal, audio alarm, motor current, vehicle count |
| Signal light | LoRa | Line | Aspect, lamp current / voltage / temperature, burn hours, fault flag |
| Axle counter | LoRa | Line | Section occupancy, axle count, last-train speed / direction / weight |
| Catenary monitor | HaLow | Line (25 kV env.) | Voltage, current, wire tension, contact wear, arcing, icing |
| Bridge strain | LoRa | Battery / solar | 3× strain gauges, tilt, displacement, deck temperature, train load |
| Predictive maintenance | HaLow | Line (depot) | Bearing temperatures, gearbox oil, wheel-flat signature, health score |
Station gateway
Raspberry Pi-class SBC, DIN-rail IP54, PoE or 12–48 V DC. Three receivers: LoRa (SX1276) for km-reach battery nodes, Wi-Fi HaLow for waveform-class payloads, HTTP for the bench.
H9 · oneM2M uplinkThe radio rule
LoRa for tiny periodic payloads at kilometre reach on batteries; HaLow where the payload is a waveform — catenary electricals, vibration features — and line power exists.
LoRa · 802.11ah HaLowWayside guardians
The perception exception: camera (+ lidar at high-risk sites) with an edge NPU at crossings, portals, platform ends and slip zones. Detections — not video — ride the FRMCS network; these are 5G devices, not LoRa nodes.
H12 · anti-collision tier
Certified where it counts
The standards each box answers to.
| Where | Power | Backup | Environment / certification |
|---|---|---|---|
| Core cluster | DC feed, dual PDU | UPS + generator | Data-centre class; HSM FIPS 140-3 |
| Radio site | AC | 8 h battery, solar-hybrid option | IP55 cabinet, EN 50121-4 EMC, −33…+55 °C |
| Station edge | AC/DC | 4 h battery | ETSI EN 300 019 indoor/cabinet |
| Dock + drone | Lineside AC / tether HV | Launch-and-hold battery; descent reserve | Outdoor shelter, self-heating; airframe certification envelope |
| On-train estate | Train battery bus | Train-native | EN 50155 (temp/shock/vibration), EN 45545 fire |
| Handhelds / wearables | Battery | Shift-length + hot-swap | IP67, drop-rated, glove UI |
| IoT nodes | Battery / solar | Years-scale duty cycle | IP67, lineside |
Simulator = hardware contract. Every field device has a simulator that emits the exact wire format of the real firmware — so software never waits for hardware, and a new corridor is tested end-to-end before the first cabinet ships.
Want the full bill of materials, spec by spec?
The design document goes one level deeper — every unit, every interface, every certification target, from the RU front-end to the axlebox sensor.