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Author Topic: Choose signal in drive-thorugh station  (Read 424 times)

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Offline Jymmy097

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Choose signal in drive-thorugh station
« on: October 10, 2018, 01:50:44 PM »
Hi everybody,

I was reading about signals in Simutrans on this page (https://sourceforge.net/p/simutrans/wiki/Signal%20guide/). Speaking of drive through stations and choose signals it says:

Quote
never place a choose signal at a drive-through station if not every train stops there. Trains will understand it as a choose signal for their destination, however far it might be. If the train does not get stuck right their, it will reserve the complete route to it's destination, blocking all other trains from using it. This does usually not result in a deadlock, so there might not even be a notice about stuck trains.

But let's suppose I have five stations A,B,C,D and E connected with rails and I have one kind of train that stops on all three, another one that stops only in A, C and E and another one that goes back and forth A and E without stopping at B, C nor D. If I want all the station to support multiple platforms (because I'd like to have more trains for each kind), how can I make them choose a free platform in B, C and D if I cannot use the Choose Signal because of the third (or second) kind of trains?

Thanks in advance.

Offline Ters

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Re: Choose signal in drive-thorugh station
« Reply #1 on: October 10, 2018, 02:38:31 PM »
As long as you think of each station as a single uniform station, you can't and/or shouldn't.

First of all, if some trains stop at the station for more than an instant (that is, they wait for a minimum load) and others don't stop at all, then the former must somehow be routed to platforms that are not located on the shortest path through the station. Trains that do not stop at the stop will always go for the shortest route through the station, no matter what signals you use. You can use waypoints to micromanage their path through the station, but this will get hard to remember as you add more routes.

Unless trains on the same line are really tightly spaced, chose signals don't help much if the trains do not wait for a full load. Just give each line its own platform. Lines with very few trains may even share a platform, as conflict would be rare.

In the cases where I have some trains waiting for a load, and some just passing through or stopping without waiting, I have one or two platforms on the main tracks for them. The rest of the platforms are off to the side (so they are not the shortest path), and the tracks to them branch of the main tracks a train length or two before the station. The chose signal, if needed, is at least one train length after the side track branches of from the main tracks, and all paths leading from the side platforms back to the main tracks have an end-of-chose sign(al). All platforms have unidirectional train movements, unless the station is a cul-de-sac. (Probably not easy to understand, but I don't have the ability to do any drawings at the moment.)

Playing style may have some impact on what works or not, though. This is the experience I have built up. Others may play differently and come up with different solutions.

Offline Vladki cz

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Re: Choose signal in drive-thorugh station
« Reply #2 on: October 10, 2018, 05:37:04 PM »
I think that putting end of choose sign on the exit track should prevent the reservation to final destination.

Offline Ters

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Re: Choose signal in drive-thorugh station
« Reply #3 on: October 10, 2018, 05:45:45 PM »
I think that putting end of choose sign on the exit track should prevent the reservation to final destination.
Maybe, but it still would not make things work the way I think Jymmy097 wants. Most importantly, trains could still chose to stop and wait on the platform straight ahead, blocking later trains that only want to pass straight through. A possibility is perhaps to not put a platform there at all, but depending on the overall layout of the station, that might look odd and require knowing the trick to building split stations.

Offline Vladki cz

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Re: Choose signal in drive-thorugh station
« Reply #4 on: October 10, 2018, 08:44:15 PM »
That is true. You can also put one more end of choose sign on the platform with shortest path. That way only trains that are scheduled to stop there will use it.

Also in extended, the choose signal looks for alternative routes even for non stopping trains. Moreover it has third aspect to show that the train is routed to alternative path.

Offline prissi

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Re: Choose signal in drive-thorugh station
« Reply #5 on: October 11, 2018, 03:33:48 AM »
The end of choose signal does negate a choose signal. It just end the SEARCH for a free route, if this is the only route to the station. Instead the train will wait for the current route to become free. BUT if there is another choose signal following on the route, the first choose signal will act as a normal signal.

Offline Ters

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Re: Choose signal in drive-thorugh station
« Reply #6 on: October 11, 2018, 05:45:15 AM »
You can also put one more end of choose sign on the platform with shortest path. That way only trains that are scheduled to stop there will use it.
I think I've actually done that. I certainly did consider it. However, it was on a cul-de-sac station, so I have no experience on how trains simply passing through would react. The "unpredictable" nature of chose sign(al)s means that I avoid using them except for stations/stops where multiple trains/trucks on the same line may end up waiting for a full load concurrently. That means I only use it for freight trains, and my freight stations do not usually have trains passing through them without stopping. If there is more than one line serving the station, I ensure that there are platforms not behind the chose signal so that vehicles for one line won't occupy all the platforms, typically for trains delivering supplies to a mid-chain factory. I might even have multiple chose signals covering different platforms, although at that point, multiple stations might be better to avoid unintended goods flows.

Offline Jymmy097

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Re: Choose signal in drive-thorugh station
« Reply #7 on: October 12, 2018, 04:23:32 PM »
Hi,

So as I can understand, choose signals are equivalent to path signals in openttd.

I'm only a beginner in the world of transport simulation games. So I can understand a cul de sac station is a station where trains can enter on both sides, am I right?

By the way, is there some reference for track architectures (ie. something like the simutrans equivalent of the openttd wiki, which is far more detailed than the simutrans one)?

Thanks a lot

Offline Ters

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Re: Choose signal in drive-thorugh station
« Reply #8 on: October 12, 2018, 05:44:25 PM »
So I can understand a cul de sac station is a station where trains can enter on both sides, am I right?
No, the opposite.

Offline Jymmy097

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Re: Choose signal in drive-thorugh station
« Reply #9 on: October 13, 2018, 08:20:15 AM »
No, the opposite.

LOL. I told you I am only a beginner. Quod erat demonstrandum.  ;D ;D

Where can I find some references to learn more about all the terminology and the architectures of rail tracks and stations and, more generally, for all types of transportation?

Thanks.

Offline Ters

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Re: Choose signal in drive-thorugh station
« Reply #10 on: October 13, 2018, 08:33:34 AM »
I just pick it up from all over the Internet, including this forum. I might get it wrong some times. Then there are a few terms that are unique to Simutrans, or rather carry a different meaning than in the real world.

Offline prissi

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Re: Choose signal in drive-thorugh station
« Reply #11 on: October 13, 2018, 01:54:01 PM »
OpenTTD has very different stations, since throughput is essential there. Most Simutrans stations are much smaller, since stations are expensive to maintain, so usually people just build the bare minimum. Looking at online games gives a good indication what people do.But nothing is currently online ...

Offline Jymmy097

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Re: Choose signal in drive-thorugh station
« Reply #12 on: October 15, 2018, 08:39:40 PM »
But as for track layout can the openttd wiki be used as a reference in simutrans?

Offline Ters

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Re: Choose signal in drive-thorugh station
« Reply #13 on: October 16, 2018, 05:58:48 AM »
I think I do things quite differently in Simutrans than I did in Transport Tycoon. It might have something to do with having matured as a planner, but I think the rather fundamental differences in how signals and routing work are more to "blame".

The principles in Simutrans are very simple. Vehicles go from waypoint to waypoint along the easiest possible route (simply put: shortest and straightest). Other individual vehicles have no impact as to which route is chosen. Once a route is chosen at departure, a vehicle will stick to it stubbornly unless you remove the road in front of it, block it with no-entry signs or similar, or change the schedule. So just make sure two trains will never meet head-on, and then start experimenting with how to make things flow best. Regular one-way signals are the bread and butter of a Simutrans signaling system, and virtually any railroad network with more than one train will need signals. Other signal types, even two-way regular signals, solve very specific problems. It is always possible to do without them, although it might be more expensive. (It is possible to do without any signals at all, but the workarounds would be far more obvious and tedious.)