YAPP – Yet Another PBS Patch

Since a few days a nice patch is discussed at the tt-forums. It is another try to implement PBS in OpenTTD. The first idea of PBS is almost three years old. The old PBS was only supported by NPF (the old ‘new-pathfinder’) and since YAPF became the common standard the development was not continued.
We are currently running a dev server with YAPP (r12062M)
IP: dev.openttdcoop.org:3982
You can find the password at our irc channel: #openttdcoop.dev @ irc.oftc.net

This new patch looks really promising. The code is clean and fits to the standard openttd developers prefer. Now, lets have a look at the details.


  • Works with NPF and YAPF.
  • Implements a signal system similar to the one Tekky described (without real bi-di tracks).
  • Is fully backwards compatible, normal and PBS signals can be used in parallel.
  • Can colour the reserved paths.
  • No known bugs (well, unknown bugs on the other hand…)


Either you are able to compile the game or you can use BuildOTTD (Windows only).

svn co -r 12062 svn://svn.openttd.org/trunk openttd-yapp
cd openttd-yapp
curl -L http://www.tt-forums.net/download/file.php?id=85483 > yapp.patch
patch -p0 -i yapp.patch
./configure && make

If you want to activate the highlighted tracks, start OpenTTD with:
./openttd -d pbs=2 or use the console command (^) debug_level pbs=2

Please check Michi_cc’s post as well and join our Dev-Server

So far the patch is pretty stable in multiplayer.

Download pre-compiled Version

9 comments so far

  1. Tim February 6, 2008 21:59

    I uploaded a compiled and under win xp working version…

  2. Sedontane February 7, 2008 07:50

    And its AWESOME!

  3. tneo February 7, 2008 08:39

    One of the disadvantages of PBS was the huge amount of CPU calculations needed, making gameplay slower then normal. Is that resolved with this new YAPP?

  4. Tim February 7, 2008 13:26

    I can’t give you facts, but surely it will take more CPU load than normal signalling, but that is due to the whole system and can’t be avoided, i guess…

  5. Osai February 7, 2008 16:02

    We provide binaries for Win32 now (thx Yorick & Tim).

  6. Volatar February 11, 2008 22:54

    Honestly I don’t know how PBS works in the first place, where can I go to have it explained to me?

  7. […] Michi_cc released Version 4.1 of YAPP, an urgent reason to update We are using r12168M now. Enjoy playing. […]

  8. […] this article we wrote about this new engine before and now we are testing it on our Public Server Game 101. […]

  9. […] Path Based Signaling Patch’ a.k.a. [YAPP] to the trunk (information from developer). We reported about this interesting patch in february ‘08 first and played a PBS game on our Public Server. I am really looking forward […]

Leave a comment

Please be polite and on topic. Your email-address will never be published.