The coaster cars were being transported, two to a flat-bed tow truck, towards EPCOT. The vehicles were wrapped in cellophane to protect them on their journey.
The two cars are sat on a makeshift roller coaster track to keep the wheels sitting properly. This will then be connected to an actual piece of track, and the cars rolled off the bars and on to the line of the ride.
We were able to get right up close to the wheel assembly as the truck drove along. Even when installed in the ride, few but the ride maintenance workers will get such a close-up, detailed view of these working parts of the coaster.
The wheel assembly consists of the three wheels together that grip the tubular steel roller coaster track. The wheels on the bottom are called the underfriction or up-stop wheels, which hold the coaster to the track and stop it from flying off on a hill. The side friction wheels can run on either the outside or inside of the track, and help keep the train from sliding left or right during the ride. These side friction wheels are located on the outside of the track. Finally, the top wheels are called tractor wheels, or running wheels, and they are the wheels that take the full weight of the train and roll it along the track. These wheels may lift off the track during an airtime hill or loop, but the up-stop wheels stop it from going… up.