PlayStation 1.0.4 Frozen Tram Signal Trigger Recipe

Run Sandbox route 1 down to Hauptbahnhof.

Leave as expected on return run, but do not make the right turn off the Avenue to the West Bahnhof stop.
Just sit as if the signal were stop.
Now that signal will cycle to Stop, but

even 5 minutes later, pulling far enough forward to get violated will NOT unfreeze the signal ... it is frozen.

This reveals a good deal about the code design for these tram signals and in my career inwould see this as indicating a likely code rewrite from design thru code review by a more senior developer than the author of that code.