A model of an insulated rail joint for H0 scale. 

It wasn't modelled for a specific rail code, but I tested it on Lima and Fleischmann rails.

I printed it in PETG with a 0.4mm nozzle at a layer height of 0.2mm, lying flat on the build plate. No supports are needed, but good cooling is recommended. Before using it for the first time, it is recommened to place it upside down on a piece of rail to remove any strings that may be inside it, which can cause the joint to break when inserted normally.