Amazon.com: LEGO Parts, Bricks, and Pieces - Black Train Parts Combo Pack (2 X Buffer Beam with Sealed Magnets and 2 X Train Wheel RC, Holder with 2 Black Train Wheels) : Toys & Games
Big Ben Bricks LLC
New LEGO Train Wheel Car Assembly - Blue Base 6 x 28 (Wheels w/ metal axle) | eBay
Resources – Brick Train Depot
Big Ben Bricks LLC
Train Wheel RC, Spoked with Technic Axle Hole and Counterweight, 37 mm D. (Flanged Driver) : Part 85489b | BrickLink