A mainstay of indie filmmakers everywhere is the skateboard dolly. Skateboard dollies use skateboard wheels — hence the name — attached to a sheet of plywood with the option of adding a push bar. The wheels are then places onto track for a smooth ride. Skateboard wheels have built-in bearings making them easy to work with and since they are available everywhere skateboards are sold they are easily replaceable and fairly cheap. The film track is stainless-steel tubing 24.5″ apart on center. It usually collapses like a parallelogram for transport, has a flat base for shimming and leveling and interlocks with the next track section. Curved pieces are available too.