Parts of a Steam Train – Labeled Steam Locomotive

All 26 parts on the diagram

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Boiler and fire 11

Boiler Hot gases from the fire pass through tubes inside it. They boil the water.
Smokestack Smoke and used steam go up and out here. British railways say chimney.
Headlight Lights the track ahead at night.
Smokebox Smoke collects here before it goes up the smokestack.
Smokebox door Opened to clean out the ash from the smokebox.
Bell Rung as a warning when the engine starts or passes crossings.
Steam dome Collects the driest steam, high above the water.
Sand dome Holds dry sand dropped on the rail to stop wheels slipping.
Safety valves Let steam out if the boiler pressure gets too high.
Whistle Blown by steam to warn people on or near the track.
Firebox Coal burns on the grate inside it. The fireman feeds it from the cab.

Wheels and rods 10

Driving wheels The cylinders turn these; on this engine there are three a side.
Cylinder Steam pushes a piston back and forth inside it.
Pilot Pushes things off the track; also called the cowcatcher.
Piston rod Carries the push of the piston out of the cylinder.
Crosshead Joins the piston rod to the main rod. It slides in its guides.
Main rod Turns the push and pull of the piston into the wheel turning.
Side rods Link the driving wheels so they turn together.
Valve gear Times the steam into the cylinder and sets forward or reverse.
Pilot truck Guides the engine into curves; also called the leading truck.
Trailing truck Carries the weight of the firebox and cab.

Cab and tender 5

Cab The driver and the fireman ride here; its floor is the footplate.
Tender Carries the fuel and water the engine uses on the run.
Coal space Holds the coal the fireman shovels into the firebox.
Water tank Holds the water the boiler turns into steam.
Coupler Joins the engine, the tender and the train.

How this list was compiled: Part names checked on 2026-09-29, a name kept only when both sources use it. Wikipedia, Steam locomotive components, text only (smokebox and smokebox door, chimney or smokestack, boiler, steam dome, sand dome, safety valve, whistle, bell, headlight, firebox, cab, cylinder, piston rod, crosshead, connecting or main rod, coupling or side rods, valve gear, driving wheels, leading or pilot truck, trailing truck, pilot or cowcatcher, tender, coal bunker, water compartment, coupler). Locomotive Dictionary (Association of American Railroad Master Mechanics, 1906, public domain), full text at https://archive.org/details/locomotivedicti00assogoog (smokebox, firebox, steam dome, sand box, safety valve, crosshead, main rod, side rod, valve gear, driving wheel, engine truck, trailing truck, piston rod, smoke stack, pilot, whistle, bell, headlight, cab, tender, coal space, water tank). The Crosshead article on Wikipedia was also read. Licence: own work

The drawing: Drawn for this site on 2026-09-29 from plain geometry, a composite of no one class or railway. Licence: own work

How it works

A steam train burns coal in the firebox, boils water in the boiler, and uses the steam to push pistons that turn the wheels through a set of rods. This drawing names the parts you can see from the side.

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Engine above, tender below

The top row is the engine, front to the left. The bottom row is its tender, drawn uncoupled so both fit a phone screen. Numbers 1 to 8 are the big parts; the rest are the boiler fittings, the rods and the tender's load.

Follow the steam

Steam from the boiler goes to the cylinder (6). It pushes the piston rod, the crosshead slides back, and the main rod turns the middle driving wheel. The side rods pass that turn to the other two.

This engine is a 2-6-2: 2 pilot truck wheels, 6 driving wheels and 2 trailing wheels, counting both sides.

Questions and answers

What are the main parts of a steam train?

The boiler, where water is turned into steam; the firebox, where coal burns; the cylinders and rods, which turn the driving wheels; the cab, where the crew work; and the tender, which carries the coal and water.

What is the front of a steam train called?

At the very front is the pilot, often called the cowcatcher. Above it is the smokebox with its round door, the headlight and the smokestack, or chimney.

What do the rods on a steam train do?

The main rod joins the crosshead to a driving wheel and turns the piston's push into the wheel turning. The side rods, or coupling rods, link the driving wheels so they all turn together.