This is a 2-truck Shay Locomotive. Commonly used for logging in the late 1800s. It has two cylinders, mounted on the right side of the boiler, connecting through a series of bevel gears and universal joints, providing power to all the axles on the engine. The boiler is offset to balance the weight of the cylinders. This gives the engine a unique asymmetrical appearance. My model uses Power Functions with a medium motor in the tender and the battery and IR sensor in the giant log on the skeleton car behind the engine. At the end is a classic red caboose to complete the train. Through several iterations, I worked out all the kinks so that it runs continuously on curved and switch tracks with ease. Check out the entire Flickr album to see a short video of the engine in action!