Manufacturing line/Rail systems/Track system
Autonomous · Rail systems

Track system

Welded rail on concrete ties, with fibre in the shoulder that hears every train, every flat wheel and every crack, and wayside units that set every switch.

Phase 6 · 2033+Concept design
Axle rating
36 t
Line speed
130 km / h
Sensing
every metre
Wayside unit
every 80 km
I · Blueprint
Side elevation, live systems
SIDE ELEVATION · 30 m OF LINE AT A WAYSIDE UNIT AND TURNOUT01020304050607080910111213141516171819Ties at 610 mm · 300 mm of ballast under the tie · 36 t axle rating · 130 km/h line speedSECTION A–A · FORMATION, LOOKING ALONG THE LINE1,435 mm gaugeTie 2.6 m300 mmRail — 68 kg/mBallast — graniteSub-ballast — 150 mmSubgrade — compactedConcrete tie — prestressedFibre in the troughShoulder — 400 mmDETAIL B · RAIL AND FASTENING186 mmHead-hardened — 390 HBStrain gaugeElastic clip — 12 kNPad — 10 mmConcrete tieHead 74 mm · web 17.5 mm · foot 152 mmDETAIL C · SWITCH MACHINE, PLANSwitch machine — 1.1 kWThrow rod — 127 mm in 3 sDetection rods × 2Switch rail — closedSwitch rail — openStock railHeater — 6 kW per sideMoves only on a command from the SIL 4 interlocking.
01Rail — 68 kg/m, head-hardened, weldedStructure
02Elastic fastening and padStructure
03Concrete tie — 610 mm spacingStructure
04Ballast — 300 mm crushed graniteStructure
05Sub-ballast — 150 mmStructure
06Subgrade — compactedStructure
07Sensing fibre — 1 m channelsSensing
08Hot-bearing and hot-wheel scannersSensing
09Wheel-impact load detectorSensing
10Rail temperature and stress sensorSensing
11Track cameraSensing
12Dragging-equipment detectorSensing
13Grid feed — 480 VPower
14Hut battery — 30 kWh, 110 V DCPower
15Switch heaters — 2 × 6 kWPower
16Wayside hut — 2 light AI modulesControl
17Interlocking — SIL 4, 2-out-of-3Control
18Switch machine — 1.1 kWControl
19Radio mast — movement authorityControl
II · Power & drivetrain

The hut that runs 80 km.

Each wayside unit powers and reads 80 km of line: fibre interrogators listening 40 km each way, detectors that check every wheel, and the SIL 4 interlocking that sets the switches and sends movement authority by radio. A 30 kWh battery carries it through a grid outage.

Wayside unit & turnout — rotating view
A wayside hut beside a turnout. Inside, the interlocking, the AI modules and fibre interrogators, and the battery. On the track, the switch machine throws the switch rails on the interlocking’s command, with heaters along the stock rails. The mast carries the train radio and a track camera.
01Wayside hut — 3.6 × 2.4 m
02Racks — interlocking, AI, interrogators
03Battery — 30 kWh LFP, 110 V DC
04Radio mast — 5.5 m, track camera
05Switch machine — 1.1 kW
06Switch rails — 127 mm throw
07Heaters — 2 × 6 kW
08Fibre trough — 40 km each way
Switch machine — motor and ball screw
Motor110 V DC, 1.1 kW
DriveBelt 3:1 and ball screw, 5 mm lead
Throw127 mm in 3 s
Force6–10 kN
LockLocked in both positions
DetectionTwo rods, proved by the interlocking
Naked system — hut power, sensing and control
Grid · 480 V three-phase50 kVA feed480 V ACSwitch heaters2 × 6 kW per turnoutHVAC · 1.5 kWhut held at 25 °CRectifier & charger110 V DC · 5 kW110 V DC HUT BUSBattery · 30 kWh LFP40 hr of DC loadInterlocking · SIL 43 × 12 W, 2-out-of-3AI modules A & B2 × 35 WFibre interrogators2 × 60 WRadio & network150 WDetectors & cameras200 WSwitch machine · 1.1 kW127 mm in 3 sonly via interlockingTrains · locomotive SIL 4movement authority by radioSENSING FIBRE · 40 KM EACH WAY · 1 M CHANNELS · 2.5 KHZFibre, scanners and strain gauges read every wheel
III · How it is put together

Grade, ballast, tie, rail, weld, wire.

The formation is graded and compacted, then the sub-ballast, ballast and ties go down and the rail is threaded in long strings. The strings are welded and stress-neutralised at 35 °C and the track is tamped; the fibre, huts and switch machines follow. The loop replays the build order.

I
Formation graded, sub-ballast laid
II
Ballast and ties placed, rail threaded
III
Rail welded, neutralised at 35 °C, tamped
IV
Fibre, huts, switch machines and detectors
V
Tested and commissioned
IV · Specification

Design specification.

Design targets for the autonomous track system.

Gauge
1,435 mm
Rail
68 kg/m, head-hardened
Ties
Concrete, 610 mm
Ballast
300 mm granite
Axle rating
36 t
Line speed
130 km / h
Rail bending stress
133 MPa at 36 t
Deflection
2.3 mm at 36 t
Fibre sensing
1 m channels, 2.5 kHz
Fibre reach
40 km each way
Wayside unit
every 80 km
Interlocking
SIL 4, 2-out-of-3
Switch throw
127 mm in 3 s
Switch heaters
2 × 6 kW
Hut power
480 V grid + 30 kWh
Neutral temperature
35 °C
Onboard compute
Two light AI modules listen; a SIL 4 interlocking decides
Modules2 light AI modules and a SIL 4 interlocking of three safety controllers, per wayside unit
CPU16 cores (2 × 8) + 2 lockstep real-time cores per module; 12 lockstep cores in the interlocking (3 × 4)
AI throughput3,000 TOPS total (2 × 1,500) — fibre acoustics, wheel, bearing and camera models; interlocking 3 × 40 TOPS
Memory64 GB at 300 GB/s per module; 60 s of raw fibre data held in memory
Power draw70 W AI + 36 W interlocking; ≈ 0.7 kW for the hut’s DC loads with interrogators, radio and detectors
Process node2 nm-class modules; safety controllers on a mature 16 nm node, 15-year supply. Compute is line-replaceable, swapped at mid-life
RedundancyEvery sensor is wired to both modules. Module A is primary for the 40 km east of the hut, module B for the 40 km west; each is hot standby for the other. The interlocking votes 2-out-of-3; any disagreement sets every route to stop.
Sensors2 fibre interrogators on the sensing fibre, hot-bearing and hot-wheel scanners, a wheel-impact load detector, a dragging-equipment detector, 2 track cameras on automotive Ethernet, rail temperature and stress sensors, a weather station
Safety sensorsThe interlocking reads its own: axle counters at every block boundary, two detection rods and lock contacts on every switch, the switch-machine current
LinkFibre backbone along the line at 10 Gbit/s; train radio to every locomotive in the 80 km
Switches move and movement authority goes out only through the SIL 4 interlocking. Axle counters prove every block clear, and two detection rods prove every switch closed and locked. The AI modules can only ask: a flat wheel, a warm bearing or a cracking rail becomes a request for a speed restriction or a stop, which the interlocking applies within its rules. The switch drive closes its current loop at 1 kHz. A software fault can never drive the track system outside its certified safe envelope.
Today vs IC
Structure and sensing: today’s heavy-haul track beside the IC design
Today · North American heavy-haul main lineIC design
Rail136 or 141 lb/yd (67.5–69.8 kg/m) continuous welded rail68 kg/m head-hardened welded rail, neutralised at 35 °C
Ties and ballastAbout 3,250 wood ties per mile at 19.5 in, or 2,640 concrete ties at 24 in; about 12 in of ballastConcrete ties at 610 mm (2,640 per mile); 300 mm of granite ballast
Axle load286,000 lb cars standard (32.4 t per axle); 315,000 lb on select lines (35.7 t)36 t per axle on every line
SpeedClass 4: 60 mph; Class 5: 80 mph130 km/h (81 mph) line speed; trains run at 120 km/h
WaysideTrain-control interface units; hot-box and dragging-equipment detectors at intervalsFibre hears every metre, every second; scanners and impact detectors at every hut, 80 km apart
The IC column is the design shown on this page. Sources for the Today column are listed in BUILD_NOTES.md.
Runs on The Brain
The track reports to The Brain: every train it hears, every flat wheel, every warm bearing and every rail that starts to crack.
See how it works →
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Line pipe →← Autorack