[ARC5] Locomotives

[Neil]

When a steam locomotive is stationary, the crank pins on the driving wheels
may be at rest in the same horizontal plane as the wheel bearings, with the
driving gear either fully retracted or fully extended. This means there will be
no motive force applied to the wheels at start-off, just when it is most needed.

For this reason, the crank pins on the left side of the locomotive are offset 90
degrees from those on the right, so at start-off only one side actually gets the
train moving until the wheels have rotated a few degrees.

73 de Neil ZL1ANM