A: James, prototype steam locomotive drivers must be “quartered,” which means that the piston rods on opposite sides of the engine are attached to the wheels one quarter of a turn (90 degrees) away from each other. This is essential for the drivers to rotate smoothly given the pushing-and-pulling motion of the rods. Side rods on each side of the locomotive connect all the drivers so they rotate at the same rate.
Good quartering is also essential on model locomotives with worm gearing on one axle. That’s because the wheels on the non-geared axles get their rotational thrust through the rods, just as on real locomotives.
On your model, the drivers are rotated through a series of spur gears, which cause both sets of wheels to move in tandem, regardless of where the piston rods are in relation to each other. Precise quartering is not essential – in fact, the locomotive will run just as well with the rods removed.
Lionel attempted to at least give the appearance of driver quartering on spur-geared engines, but in the rush of mass production some models came off the line without any regard to it, so long as the drivers on each side were lined up and the side rods didn’t bind.
Quartering locomotive wheels requires special tools, which Lionel provided to authorized service facilities. We don’t recommend that you try it at home without them.