The 9U kit locomotive allowed a child to see the glories of Lionel's engineering firsthand, by building a locomotive from the ground up. Armature, field, brushes, and other parts were assembled into the famous Bild-a-Loco motor using tools supplied in the kit. Once the motor was done, the builder could add the parts needed to create a locomotive, complete with manual reverse knob on the outside - or, by using a pulley shaft instead of wheels, make the motor into a stationary 3-speed power plant. Unassembled 9U kits in the original box are extremely rare and valuable today; but you can own this Lionel Corp. reproduction for a very reasonable price, in either the original orange or dark green.