* Add 4 Part 55423c01 Black Train Wheel RC Train, Spoked with Technic Axle Hole and Rubber Friction Band (Extra)
* Change {8 to 4} Part Black 55423c01 Train Wheel RC Train, Spoked with Technic Axle Hole and Rubber Friction Band
Comments from Submitter:
Only 4 wheels of this type are needed for the engine, so 4 wheels are extra.