Rail and bulk transport
Move mass cheaply overland.
Everything for this step
- Field guide
- None yet. A guide goes deeper than a step: technique, identification and the hazards.
- Builds
- None yet.
- Reference sheets
- None.
- Sciences it rests on
- Engineering · Physics
- Track
- On land, level 2 of 3 · next: Internal combustion and mobility
Why this matters
Rail cuts land freight costs by an order of magnitude, which redraws where it is worth mining, farming and living. It also forces the first true standardisation across a whole society — gauge, time, signalling — and that habit spreads far beyond the railway.
The shape of it
- Grade gently. Steel wheel on steel rail has almost no friction, which is the whole advantage — and almost no grip. Keep gradients shallow and curves wide, even at large earthwork cost.
- Build the trackbed properly: drained formation, deep ballast, sleepers, and rail fastened to allow thermal movement. Rail buckles in heat and cracks in cold, and most derailments trace back to the bed, not the vehicle.
- Pick one gauge and never change it. Break-of-gauge means unloading and reloading every wagon at a boundary and it silently destroys the economics.
- Signal it before you need to. Two trains on one track is the failure mode, and it is fatal. Block working — only one train in a section, with positive confirmation before the next enters — is the discipline that makes railways safe.
- Standardise time. Railways are why clock time became uniform across regions: you cannot run a timetable when every town keeps its own noon. Expect the same requirement.
- Then reconsider water. Canals and rivers still beat rail on cost per tonne-kilometre for bulk goods where the route exists. Build rail where water cannot go, not where it already does.
Doing it, step by step
The summary above says what has to happen. This says how, with the numbers that decide whether it works.
1 · Survey for gentle gradients and wide curves
Steel wheel on steel rail has almost no rolling friction — about 2 kg of resistance per tonne on the level — and almost no grip. A gradient of 1 in 100 adds about 10 kg per tonne, roughly five times the level resistance, so grade alone decides how much a locomotive can haul.
Keep the steepest grade on a main route — the ruling gradient — around 1 in 100 or flatter, and curves wide, several hundred metres in radius where speed matters, even at large earthwork cost. The ruling gradient sets the train load for the whole route forever.
2 · Build a drained formation and a deep ballast bed
Most derailments trace back to the bed, not the vehicle.
- Formation: the earthwork, sloped to side drains so water leaves it.
- Ballast: clean, angular broken stone, at least 20–30 cm deep under the sleepers, which spreads the load and drains.
- Sleepers at about 60–70 cm spacing.
- Rails fixed so they can move with temperature: leave expansion gaps at joints sized to the temperature at laying — larger when laid in cold weather.
Rail buckles in heat and cracks in cold.
3 · Pick one gauge and never change it
Break of gauge means unloading and reloading every wagon at a boundary, and it silently destroys the economics. Pick one gauge for every line that could ever connect — 1,435 mm is the most common in the world — and hold it with a track gauge tool, checked on every length laid and on inspection.
Write the gauge and its tolerance into published law so every future builder is bound by it.
4 · Signal by blocks, before you need to
Two trains on one track is the failure mode, and it is fatal. Running trains a set time apart — time-interval working — was the historical cause of most collisions.
Block working: the line is divided into sections, and only one train may be in a section. The next train enters only after positive confirmation that the section is clear — by telegraph between signal posts. On single lines, a token — a physical staff or tablet, one per section — is carried by the driver, so no train can enter without it. Later, interlock points and signals so conflicting signals cannot be shown.
5 · Standardise time across the line
You cannot run a timetable when every town keeps its own noon — local solar time drifts by about 4 minutes per degree of longitude. Railways are why clock time became uniform across regions.
Fix one standard time for the network, distribute it by telegraph each day, and set every station clock to it. Publish the timetable in that time.
6 · Walk the line and inspect after every storm
A washout or a broken rail kills without warning. Assign track gangs to set lengths of line, each walking their length daily looking for broken or cracked rails, loose fastenings, gauge spread, and ballast washed out.
After every heavy storm or flood, inspect culverts, embankments and bridges before the first train, and impose speed restrictions until defects are fixed. Log every defect and its repair.
7 · Build rail where water cannot go
Canals and rivers still beat rail on cost per tonne-kilometre for bulk goods where the route exists. Compare the two for each route before building: cost per tonne-kilometre, including the capital.
Build rail where water cannot go — over watersheds, into mines and quarries, to inland towns — not where it already does. See wheel, cart and road.