When looking for a support for the wooden train track of my son I found one by sir_indy (https://www.thingiverse.com/thing:2025414). This inspired me to design one which can be stacked so the trains can go even higher. The height where the track will be is 6cm and I've tested it with various brands; Brio, IKEA, Playtive (LIDL).

There are 2 versions of the model, a normal one and one where I added a sort of brim on the 4 corners of the piece (0.2mm height), which should be enough so you do not need to print using a full brim. Designed to be printed at 0.2mm layers or thinner (no 0.3mm).