How the Steam Train Works

Order follows a top-down, front-to-back teardown: loose top fittings (chimney, dome) lift off first, the boiler shell comes off the frame next, the firebox separates from the boiler's rear, then the front motion work (cylinder, piston, rod, wheel) is undone, leaving the bare frame last.

1. 1ChimneyVents spent steam and smoke to the atmosphere and, with the blast pipe below it, creates the draft that pulls the fire hotter.
2. 2Smokebox & Blast PipeHouses the blast pipe that fires exhausted cylinder steam upward into the chimney, turning used steam into a hotter fire.
3. 3Steam Dome & RegulatorCollects the driest steam from the top of the boiler and its regulator valve is the throttle deciding how much enters the engine.
4. 4Boiler BarrelThe main pressure vessel: water surrounding the fire tubes is heated by hot gas from the firebox until it turns into high-pressure steam.
5. 5FireboxThe chamber where coal is burned on a grate, supplying the heat that the boiler turns into steam.
6. 6Cylinder BlockReceives steam from the regulator through the main steam pipe and lets it expand against the piston, turning pressure into a push.
7. 7Piston & RodSlides back and forth inside the cylinder bore under steam pressure, carrying that push out through the piston rod.
8. 8Connecting RodLinks the piston's straight push-pull motion to a pin on the driving wheel, turning it into rotation.
9. 9Driving WheelThe large wheel the connecting rod turns; its rim grips the rail and propels the whole locomotive forward.
10. 10Frame & ChassisThe rigid steel underframe that everything else bolts to and that carries all the forces of combustion, steam pressure and motion down to the rails.