Replacement supports for the Imaginarium line of train sets. I'm sure many different sets are compatible. These supports have a rounded channel to accommodate the curved track pieces.

The shorter support holds the track at 62mm high, and the taller one at 124mm.

They don't need to be very strong, so I printed them in the same orientation as the STL, in PLA, no supports, .2mm layers, 2 walls, 10% infill and that seems like more than enough.