A working steam engine -- just a little on the small size. The track is 15". The Sequoia is one of the Tilden Steam Train engines. I saw two others in the barn, the Oak and the Laurel. Was up there to take my granddaughter for a ride. These are the cutest engines you can imagine, and perfect in every detail. check out their website http://www.ci.berkeley.ca.us/coolthings/parks/Tilden/steamtrains.html