Steam Locomotive Diagram Worksheet

A steam locomotive diagram worksheet for middle school: 22 numbered parts, a line for each name, and a key.

Steam Locomotive Diagram Worksheet

Name Date

Numbered worksheet

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
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Write the name of each numbered part.Answer key

  1. Boiler
  2. Smokestack
  3. Cab
  4. Driving wheels
  5. Cylinder
  6. Pilot
  7. Headlight
  8. Smokebox
  9. Smokebox door
  10. Bell
  11. Steam dome
  12. Sand dome
  13. Safety valves
  14. Whistle
  15. Firebox
  16. Piston rod
  17. Crosshead
  18. Main rod
  19. Side rods
  20. Valve gear
  21. Pilot truck
  22. Trailing truck

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

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step The labeled steam locomotive, with its tender

All 22 parts on the diagram

Show the list

Boiler and fire 11

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

Wheels and rods 10

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

Cab and tender 1

  1. Cab The driver and the fireman ride here; its floor is the footplate.

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

On this steam locomotive diagram labeling worksheet for middle school, write a name on the line for each number. The engine is seen from the side with its front to the left, and number 1 is the boiler.

Read the full guide

Steam locomotive word bank

In alphabetical order, to copy onto the board: bell, boiler, cab, crosshead, cylinder, driving wheels, firebox, headlight, main rod, pilot, pilot truck, piston rod, safety valves, sand dome, side rods, smokebox, smokebox door, smokestack, steam dome, trailing truck, valve gear, whistle.

The numbers that get swapped

8 and 9 sit together at the front: 8 points into the smokebox, 9 at the curved door on its face. 11 and 12 are the two humps on the boiler; on this drawing the steam dome is the front one. 3 and 15 both stand behind the cab, and 15's line runs through it to the firebox. 18, the main rod, slants; 19, the side rods, lies flat across three wheels.

  • When marking, chimney is right on line 2, cowcatcher on 6, sandbox on 12, connecting rod on 18 and coupling rods on 19.
  • Line 4 is one name for all three large wheels, though its line points to the rear one.
  • The tender is not on this sheet. It is on the labeled steam locomotive, with its coal space, water tank and coupler.

Questions and answers

Why does a steam locomotive have two safety valves?

So that one still works if the other should fail. Each opens at the pressure it has been set for, and the two may be set to different pressures, so that a small excess in the boiler opens just one.

What does a steam locomotive burn?

Most often coal or oil; in earlier times coke or wood. A fireman shovels coal through the firebox door, and larger engines feed it with a mechanical stoker. Oil is sprayed into the firebox from a sealed tank.

Why does steam come out of a steam locomotive's smokestack?

Steam that has done its work in the cylinders is sent up the smokestack through the blast pipe, or exhaust pipe. That makes a draft, which draws the hot gases of the fire through the firebox and along the boiler tubes.

What is a steam locomotive without a tender called?

A tank locomotive: it has its water tank and coal box on an extension of the engine's own frames. A saddle tank locomotive has its water tank over the top of the boiler.

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