PBS
From #openttdcoop wiki
Contents
Description
PBS stand for Path Based Signaling, which is a different way of signaling trains when they can enter a certain track segment. Although primarily intended in OpenTDD (and in the real world) to provide bi-directional track, without the deadlocks that will occur with regular signaling. Besides that it can also be used to increase performance in certain situations.
At the time of writing, a new implementation of PBS has made its way into the development branch of OpenTTD and might thus be encountered on the #OpenTTDCoop server. The implementation, named YAPP, adds two additional signals. Because PBS takes some getting used to we've collected some examples and hints to work with.
How it works
For an explanation on the basics of YAPP and some examples, please check the YAPP page on the OpenTTD site.