Stateless by design
UE and session state lives in the UDSF (TS 29.598). Any control-plane pod — AMF, SMF, PCF — can be killed and rescheduled with zero service loss to a moving train.
3GPP TS 29.598 · Release 19The network
From orbit to axle.
A single FRMCS service layer carried by three radio skies — terrestrial 5G SA, tethered drone cells and satellite NTN — terminated by one multipath gateway on every train.
Terrestrial tier
A 5G SA core built like flight software.
The heart of FRMCS.ai is a from-scratch 5G Standalone core, engineered as stateless cloud-native functions on Kubernetes and pinned to 3GPP Release 19.
Engineered for five nines
One durable store, one in-memory store, one state path. No divergent backends, no fallback code paths — the discipline availability targets actually require.
Cloud-native · Kubernetes · GitOpsMCX service layer
Mission-critical push-to-talk, video and data (3GPP MCX) provide the bearer-level priority, pre-emption and group communication FRMCS voice and emergency services demand.
TS 23.280 · TS 24.379 · TS 33.180
Radio access
O-RAN base stations, open to intelligence.
Our gNB is a spec-grounded O-RAN O-DU: a Go control plane (F1AP, E2AP, O1/NETCONF, nFAPI) over a C data path (MAC, scheduler, HARQ, RLC, GTP-U) — the hot loop in C, the brains in Go.
Because every interface is open — E2 to the Near-RT RIC, O1 to the SMO, A1 for policy — the AI layer can retune the radio along the corridor in real time: beam patterns, scheduler weights, handover thresholds.
- F1AP / E2 / O1 / A1 — full O-RAN interface suite.
- nFAPI (SCF 222/225) PHY boundary — pair with any compliant L1/RU.
- Deterministic C data path for the microsecond-scale MAC/RLC hot loop.
- RIC-ready: xApps steer mobility for trains, not smartphones.
- Same software on mast, gantry, tunnel node — and drone.
Aerial tier · Elastic Sky
The base station that takes off — when the ground goes down.
Towers carry the everyday FRMCS network. Elastic Sky exists for the two moments they can't: disaster recovery, when floods, fires, storms or a derailment take masts offline — and rapid deployment, when a corridor needs coverage before its towers are built. Tethered drone-hosted gNB cells, docked in standby, airborne in minutes.
Standby
The drone rests docked on its corridor station — charged, sheltered, self-testing, mission-ready.
Detect
The AI watches network health and incident feeds. A mast goes dark, a derailment is declared, a new sector requests service — launch decision in seconds.
Launch
Within minutes the drone climbs to 80–120 m over the failed or unserved sector. Power and fibre fronthaul flow through the tether — endurance is unlimited.
Restore
The airborne gNB cell re-joins the same 5G core and restores REC emergency calls, voice and ETCS data across the gap — incident teams included.
Stand down
Masts repaired, or permanent towers on air? The cell descends, docks and returns to standby — ready for the next event.
Tethered = unlimited
The tether carries power up and fibre down — no battery limits, no wireless-fronthaul bottleneck, and the aircraft is physically secured over railway land.
Disaster recovery
Floods, fires, storms or a derailment take masts offline — a drone cell flies over the failure and restores FRMCS service within minutes, keeping trains moving and incident teams connected.
Rapid deployment
Where towers don't exist yet, dock stations install on existing lineside power — a corridor is live in days while permanent masts are planned, consented and built.
Altitude is coverage
From 120 m, one cell sees what three masts see — over embankments, cuttings and terrain that shadows ground-level radio.
Towers stay the workhorse
Elastic Sky never replaces the terrestrial tier — it backs it up. Day to day the drones stay docked; that discipline keeps the fleet small and the operation simple.
Fleet-orchestrated
The intelligence layer keeps every dock mission-ready — charging, self-tests, weather holds, airspace compliance — and runs launches and stand-downs autonomously.
Dual mission
The cell tower is also the train's eyes.
The same airframe that lifts the gNB carries a perception pod — camera, radar and lidar fused on an edge NPU. Whenever it is airborne — over an incident, or covering a corridor that has no towers yet — it sees kilometres beyond the on-board sensor horizon: around curves, over crests, into cuttings.
Detections stream back over FRMCS as critical advisories to the driver, dispatcher and ATO — one tether, two missions: coverage and anti-collision lookahead.
The perception tier- Sees where trains can't: a train needs 1–3 km to stop; the drone scouts that distance ahead.
- Detections, not video: inference happens on the airframe; the network carries alerts in milliseconds.
- Advisory by design: perception informs drivers and ATO; certified SIL logic alone commands brakes.
- Every pass teaches the twin: hazard maps of crossings, wildlife corridors and rockfall zones improve daily.
- 3GPP NTN (Rel-17→19) — standardised 5G over LEO/GEO, not proprietary VSAT.
- Multipath TOBA: satellite is a bonded bearer, not a fallback of last resort.
- QoS-aware steering: ETCS/ATP stays on the lowest-latency sky; CCTV archives ride orbit.
- Partner-delivered: integrated with constellation operators — Starlink, OneWeb, AST SpaceMobile, Omnispace-class — not launched by us.
- Global reach: trans-continental freight corridors, deserts, tundra, island lines.
- Continuity: the network layer that no landslide, flood or fire can take down.
Orbital tier
When the ground fails, the sky doesn't.
Satellite is FRMCS.ai's third sky: 3GPP NTN bearers delivered with constellation partners — LEO and GEO — and bonded into the same TOBA multipath session as tower and drone cells. Always overhead, whatever happens on the ground.
For railways crossing wilderness — Australian freight lines, Andean passes, Arctic corridors — orbit is not a backup. It is the primary sky, with Elastic Sky held in reserve for incidents and new-corridor deployment.
Train tier
One gateway on board. Every sky in reach.
The TOBA (Telecom On-Board Architecture) gateway terminates FRMCS on the train and presents one service layer to every on-board application, per UIC TOBA FRS.
| Application class | Examples | Preferred sky | Behaviour on degradation |
|---|---|---|---|
| Critical control | ETCS/ATP, ATO, emergency voice (REC) | Terrestrial 5G → drone cell | Seamless bearer switch; never dropped, pre-emption over all other traffic |
| Critical support | KMS, PKI, safety-device voice, advisory | Any low-latency sky | Retries with priority; session continuity via stateless core |
| Performance | TCMS telemetry, PIS, C-DAS | Best-value bearer | Buffered store-and-forward via on-train edge |
| Video / bulk | CCTV live + archive offload | Drone cell / satellite | Rate-adapted; archive syncs opportunistically at stations |
See the whole stack in motion.
From Release-19 core to drone dock to orbit — we'll walk your engineers through the architecture, spec anchor by spec anchor.