PathBasedSignalling

Enable path based signalling

Path Based Signalling

Enable path based signalling

2.0.1 alpha 41 or later

-=Switch=-

Configuration file: pathbasedsignalling on|off

Command line: -XI

-=Description=-

;'''Note''':This feature is somewhat dangerous, it may lead to train crashes if not used correctly. Please read this entire page before trying to use it.

Path based signalling is a feature that allows several trains in a signal block as long as their paths do not interfere. This greatly enhances the entrances and exits of stations as well as junctions.

The non-exclusive use of signal blocks is achieved by the trains "reserving" a path through the signal block. These reserved paths are then shown somewhat darker, and other trains will not reserve paths that interfere with them.

By default, all signal blocks which have at least one pre-signal, exit signal or combo signal leading into them will be converted to path-based signalling as soon as the block becomes clear for the first time. You can disable this by enabling the "noautomaticpbsblocks" [MiscellaneousModifications|miscmods] setting, in which case you have to set one signal in each block manually by cycling the states with Ctrl. If one signal is using path-based signalling, then all signals leading into that block will be converted to path-based signalling.

To make path-based signalling (PBS) work correctly, you have to obey the following rules in your junction design:

• Do not put another signal immediately behind a PBS signal
• The paths through the junction must be shorter than 64 tiles and cross 7 or fewer junction tiles
• Whether these signals are red or green does not matter for whether the train can pass them, except that if the train can't find a route to its destination, it will wait at a red signal, but not a green one
• The train can pass a signal if it finds a route past the signal leading out of the signal block or to its destination.
• A train will not look for paths that end at a red two-way signal
• A train will look for paths that end at a red one-way signal
• If the train cannot find a useful path at all, it will take any path if it is currently at a green signal. It will wait at a red signal.

Additional notes:

• If track pieces are stuck at "reserved" (dark), try forcing a train to run over them, or bulldoze the tile and rebuild. Sometimes this may not be obvious (if the pieces are not on a junction they cannot be darkened to show that they are reserved).
• You can tell whether a signal is using PBS by looking at it with the info tool. You can also tell by noting that a PBS signal stays green until the whole train has passed it, other signals go red as soon as the engine passes them
• PBS changes the functionality of pre-signals somewhat, because trains now enter the block even when the signal is red, as long as they find a path to a green two-way signal (or a green or red one-way signal) that leads to their destination
• This feature may require some junctions to be changed, or better waypoints for trains to find the right way
• You can use PBS to activate road crossings earlier than usual, they will now be activated as soon as a train reserves a path across them.
• You can download a demo save game [1], showing this feature in action
• This feature may still be somewhat buggy and cause both train crashes, or trains getting stuck at signals. Please report both bugs together with a savegame (in case of crashes, before the trains enter the signal block!)