We just learned about the Coupling Rod that hooks all the wheels together.
Another part of a steam locomotive is the Connecting Rod.
Remember that we learned about how steam pressure works with a steam cylinder to push and pull a piece of metal in a tube called a piston.
The piston is hooked up to the connecting rod, which takes that forward and back pushing an pulling and makes it into a circular push and pull to spin the locomotive's wheel around.
(from: wikipedia - connecting rod)
Kid Facts - Blast from the past: Rack and Pinion
