Path based signaling will allow more then 1 train on a junction at a time, provided their paths don't cross. This works by letting the trains 'reserve' the path they are planning to take. Reserved tracks are shown darker as normal tracks. (see screenshot)
You build such a PBS-junction by making all signals (entrance and exit) to that junctions PBS signals, you do this by ctrl-clicking 4 times on a normal signal.
For this patch to work, you need to put nsignalsw.grf (made by Michael Blunck) in your /data directory.
Get this file at Michael's site -> Download -> nsignalsw.zip , or in the 'new graphics' section at the TTDPatch Website.
Its best to only use 2-way signals at dead end exits, like terminus stations.
Also, PBS needs NPF (new pathfinder) enabled, otherwise it won't work.
- - the darkened track don't display 100% correctly on all tiles (not really a bug, just a gfx glitch)
- [fixed] a crashed train wont release the tracks it has reserved