First, make sure you're building the track in the right environment. For the piece you're looking for (or the one I think you're looking for) is in the 'Lagoon' environment. On your screen, from left to right it goes 'Canyon' - 'Valley' - 'Lagoon' - 'Stadium'
Once you're in the Lagoon environment, the piece you're looking for is in section 6/7 or Rollercoaster 6/7. In the 'Slope' category.
Also, remember some categories have more than one wheel on the right side. Use R1 (or RB on Xbox I'm assuming) to scroll through the other pieces that you can use. In example. The Rollercoaster section in the Slope category has 2 sets of pieces/wheels for the right side/stick to choose from.
1 people found this helpful