The linear motion of the piston rods is transformed into the revolving motion of the driving wheels through the main rod and the power of the locomotive is transmitted to the other driving wheels through the connecting rods. These are attached to the wheel cranks (NOT the axle ends). The connecting rods are overlapped from wheel to wheel using spacer bushings where necessary. The main rod is usually attached outside the connecting rods to driver two or three.
Quick facts
Steel castings
Track damage
Wheel coupling system