Changes

* ''Terminal stations''. Wherever you use bi-directional signals on a stretch of track used by more trains than a single trainthere are platforms, you need chain signals to avoid trains eventually getting stuck nose-to-nose.In this example (taken from the section on bi-directional signals above), as soon as you have three trains (one more than two, the number of platforms) you need to replace the incoming block signal with a chain signal.[[file:Bi-Directional_station.png|300px]]