I want to build a single track line something like this:
(http://i56.tinypic.com/219nkn6.gif)
(Apologies for MS Paint rubbishness)
but I'm really unsure what signalling to use, or if this layout is even possible to get working on Simutrans.
Basically I want trains to come off a double track line onto a bi-directional single track line, which has multiple single platform stations on it. The station at the very end of the line (terminus) has two platforms. The conditions I want are:
1) I want trains to be able to use either platform of the terminus station (whichever is free).
2) I don't want trains to enter the single track section unless there's a clear path ahead to the terminus. If both platforms of the terminus are occupied, or there's a train coming the other way along the single track, I want the train to wait until the path is clear.
At the moment, on the double track section, I have a one way long block signal (marked LB) for trains entering the single track line, and a one way standard signal (marked S) for trains exiting the single track line. I've also tried putting a choose signal in the location marked ??? to allow trains to use both terminus platforms, but this just seems to cause conflicts.
I think I could make this work fairly easily by putting a short 2 track section (with signals) immediately before the terminus, but I'd like to avoid this if possible.
Does anyone have any ideas? Or is this whole layout just a bad idea and a recipe for lockups? Any help would be appreciated.
EDIT: Actually, I think my problem is a bit more fundamental than the above. I can't get the layout below to work either, with just a single platform terminus.
(http://i56.tinypic.com/1565rib.gif)
Seemingly, no matter what type of signal I put at the location marked ???, I can't stop trains from merrily piling one after another into the single track section, totally ignoring the fact that there's a train already in there. I thought the long block signal was meant to stop this, but it does not seem to.
In the second picture, a long block signal where the question marks are should work. Which version of Simutrans are you playing? There were some issues with long block signals not too long ago.
Ah, OK! I was using an older version. I just tried again with Simutrans 110.0.1 (using pak64) and the 2nd picture, with a long block signal placed as you say, now works just fine! Thanks for your help with that.
Still can't find a way to get the 1st picture to work as shown though. I changed it by placing a short 2 track section just before the terminus, with a choose signal going into the station and a long block coming out, and that seems to work (although it's not my preferred layout) - see below.
(http://i52.tinypic.com/spkm14.gif)
Not sure if it will solve your problem
www.youtube.com/watch?v=0hfvIrAHiWk
Thanks for posting the link, Vonjo. I think it's a good demo of how choose signals work, but it doesn't show the situation of a single line branch with multiple platforms at the terminus.
In fact I'm unclear as to whether you can use choose signals on bi-directional single track lines at all. Every example I've seen uses a one way choose signal, with the train leaving the station on a different track than it came in on.
Quote from: RicBax on August 07, 2011, 03:08:36 PM
In fact I'm unclear as to whether you can use choose signals on bi-directional single track lines at all. Every example I've seen uses a one way choose signal, with the train leaving the station on a different track than it came in on.
That is my understanding as well. Your third picture is how I would deal with this situation.
The third picture needs to have a large enough waiting area in front of the choose signal. Otherwise it would never work deadlock free. Or you need to have a schedule, where the terminus is first and then all stations in between. Then put the choose signal before single track section.
I am curious: How would one solve this in TTD?