This time I tried something new: the goal was to build a track where the electric locomotive would pass over all pieces when set on the track. That goal is simple to reach by building a simple loop or anything else topologically isomorphic to a circle. Getting the same result with a lot of switches and having the train run back over the same piece is a lot trickier. The only assumption you need to make is that the train will take the straight rail when encountering a switch.
The second picture is right before godzilla got her fingers on the track.