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  • Can someone post a full description, with examples of the different types of signals and their use?
  • Also, can someone explain with more detail about the usage for the pre-signaling system? Hellhound 07:48, 31 May 2007 (CEST)
Will try :) -- H3llkn0wz 10:44, 31 May 2007 (CEST)
OK. Go read Building signals tutorial. Then there is Advanced signal placement a.k.a. Presignals page.
Oh, and if you want to read about standard signals, not the fancy pre-signals, well... :) I might add that a bit later. -- H3llkn0wz 13:05, 31 May 2007 (CEST)
  • I've tried to explain the change to signals to defaulting to semaphores in 0.6.0 and later because it's not clear otherwise and most graphics use the old style, I'd like this to be better explained but couldn't find the right words (Steve Roome Mon 14 Apr 2008 03:27:55 BST)


Path signals

This is an impractical waiting location -- but it is not unsafe.

Why is the text referring to "unsafe waiting location" with path signals, if the train is blocking a crossing? The path-based signalling system for example - to my knowledge - never allows the train to turn around if it cannot make a full path to the next signal. The situation in the image on the right shouldn't be stated as unsafe waiting location, but it should be called as impractical waiting location because it merely causes obstruction to other traffic. I have never had any problems with PBS, even if I have placed signals at impractical locations as shown in the image -- trains being held there at red signal blocking the junction merely cause an obstruction to the crossing traffic - but it is not an unsafe situation since the crossing traffic is held at red light. -- 19:11, 13 May 2009 (UTC)

As "safe waiting location" is a place where it is impossible to cause deadlocks. In this case the train waits at a junction which can cause a dead lock, for example when the train on the left if waiting for the train on the top to cross the junction (i.e. it makes a loop). So it's "safeness" with respect to deadlocking, not "safeness" with respect to crashing into eachother. 2001:5C0:1400:B:0:0:0:197 19:28, 13 May 2009 (UTC)
I changed the wording from "unsafe" to "bad." Calling it unsafe is very misleading and I assumed that for whatever reason the signal wouldn't be able to prevent a crash in that situation. I was already confused and this didn't help matters. I personally think the section should be rewritten to better explain them. For example:
"This is a major advantage against standard OpenTTD signals, where you had to place signals before and after junctions, which caused trains to block junctions while waiting."
I don't understand how they're different from ordinary signals in this respect. Both types of signals require signals furthers down the line, trains will be be unable to go forward at all if there's another train on the track they want to go down. Furthermore, both signals are equally capable of blocking trains if you put them right after a junction; you can fix this problem by putting the signal a little further down the line, and path signals do nothing new to alleviate this problem. Logic fail. I could explain them in two sentences: "Trains can enter the same block by reserving a path, as long as their paths do not intersect with other paths. This is an improvement over standard signals which will turn red if a train is in the same block, even if the train is not headed where it's going."
...That is how they work, right? The section is difficult to understand and I don't have enough money to test it out. Sorry if I'm formatting this wrong, I'm not used to wikis.-- 23:49, 31 January 2010 (UTC)
the difference between a junction with regular signals and one with path based signals is as follows.
consider a situation with a train waiting at the first signal beyond a junction and consider that the signal in question is sufficiantly far past the junction that the train isn't physically blocking the junction.
with regular signals while the train isn't physically blocking the junction it IS logically blocking it. Nothing else can enter the junction until the signal beyond the junction clears. If a train is trying to get through the junction the other way and all the track segments in between are full this can mean a deadlock. With path based signaling if a stopped train isn't physically blocking a route it isn't logically blocking it either. plugwash 17:41, 8 March 2010 (UTC)
As for the use of the term unsafe while the location is not unsafe in the sense of being able to cause a crash it is unsafe in the sense that it brings back the deadlock issue that proper use of path based signals prevents. plugwash 17:43, 8 March 2010 (UTC)

Should there be an explanation as to how to close of junctions with Path Signals? The article says not to put a signal there, so what does one do? 22:06, 3 August 2009 (UTC)

Added 'good' example next to the 'bad' example. FooBar 14:56, 5 July 2011 (UTC)

Any uses for old signal types?

As of OpenTTD 1.0, it seems that path signals, even without tweaking any of their setings, are far superior to other signaling methods in any kind of situation.

  • The path system can handle a lot of traffic in complex signal blocks at once.
  • Path signals can be used in place of other signal types in any setup. (as far as I know)
  • Using path signals often simplifies the signal layout.

If this is true, why do the other signal types even exist anymore? Am I missing something useful that can't be done with path signals? - 01:55, 18 April 2010 (UTC)

First of all they exists for backward compatibility. You can use your old games and play it with a recent version without creating a new game. Additionally you cannot do everything with path signals like priorities and load balancer stuff. And there is no need to delete the other signals unless you want to make room in the map array. If you want only path signals then simply use only path signals. --Progman 08:37, 18 April 2010 (UTC)
At this present moment I have a lot of problem understanding where each signal is for. Removing those unneeded signals would help me a lot. Simple, easier to understand, game mechanics and user interfaces removes a lot of confusion.

I don't understand something

Hello, I'm helping translating this wiki in french, but I've got a problem with one sentence I don't understand the meaning. I can translate a word for a word, but i would prefer understand it :)

If another train wants to enter the block, and succeeds in reserving a path through the block, both trains can use one signal block at the same time.

thanks for help


I thing I got it : i confused "Block Signals" and "signal block".

Currently I'm not sure if path signals are always safe. I had a train crash yesterday and trying to find out the reasons for it.

First of all: Is it possible that signals do not work properly when the distaster option is switched on?

Here the discription of the accident (I saw only the results):

Train1 left from a station with normal two way block signals leading to a one track lane (used in both direction). Train2 came from a intersection with a one way block signal, reverving the path up to the block signal of Train1.

The intersection is seperated form the one track lane by a block signal. There the trains crashed. Is is possible that a train enters a reserved track?

I can post a picture later on.

Signals vs real signals section

I've been writing the last part of the article to give players a sense of the difference between reality and the game, since after playing with many people they have some notion that the game is "super realistic" in its signaling system.

--Mossarelli (talk) 14:39, 28 September 2015 (UTC)

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