The 3 truck shay was king of the logging industry. It wasn't built for speed but instead to put out the maxinum tractive effort on steep grades with sharp turns on track that was maintained as an after thought! Shay Locomotives are characterized by side mounted pistons. The pistons drive a crankshaft that turns a driveshaft which transfers power to the drive wheels through gears.
This model is patterned after the J Neils Lumber Co Number 5. A 1929 Lima built three truck Shay owned by the Illinois Railroad Museum. A separate motor drives the crank and pistons. The truck gears are stationary decoration. Currently the real locomotive is not operational but is undergoing restoration and should be running again soon!
The "right" side. The side side opposite the pistons on a shay is refered to as the "wrong" side! A separate motor takes power from the LEGO train motor and drives the crank and pistons. The crank and pistons are 4 wide, the drive motor is 4 wide dictating the building of this model as an 8 wide. The truck gears are stationary decoration.
While the open topped single cylinder is somewhat absurd crowds love to see the pistons pumping and crank turning at public displays. It has run well for years with only minor adjustments to the pistons and crankshaft.
Check back as a crane car and a *.MPD file are being developed!