PBS problem

michael blunck · Post by **michael blunck** » 26 Aug 2006 09:58

Haven´t played a real game for many months, I need the help of experienced gamers because of serious trouble with PBS. The screenshot below illustrates the problem: train number 5 should take the branch to the north but never does. To enforce the right behaviour, I placed an extra waypoint directly behind the branch but even now it refuses and instead every time reserves a path (see arrow) in the wrong direction.

Could please someone explain what´s wrong with this setup? Or could it be a (known) bug in PBS, possibly?

regards
Michael

aahz77 · Post by **aahz77** » 26 Aug 2006 10:30

I can't see any signals on the tiles between the junction and the station. Could it be that the train is scheduled from the west, stop at the station and then continue north? In that case, it might be that the path from / to the west is still reserved because the train never left the pbs block while stopping at the station.

michael blunck · Post by **michael blunck** » 26 Aug 2006 10:42

> Could it be that the train is scheduled from the west, stop at the station and then continue north?

No. This train is exclusively scheduled for the north branch, the southern branch being serviced by a different train.

> In that case, it might be that the path from / to the west is still reserved because the train never left the pbs block while stopping at the station.

No. When leaving the station, train no 5 reserves that track piece anew.

regards
Michael

AndersI · Post by **AndersI** » 26 Aug 2006 11:21

Sorry if I'm asking the obvious, but how far away is the next signal on the line? There is some limit for PBS, I don't remember right now what it is. 64?

aahz77 · Post by **aahz77** » 26 Aug 2006 11:22

Hmm... Then you should convert the signals to non-pbs (there is no path-finding necessary at all in this case). But that's only a solution to the problem but no explanation, of course.

eis_os · Post by **eis_os** » 26 Aug 2006 11:32

Warning: I don't know how Josefs PBS internal works.
I am not sure if the pathfinder call works well when the reserve train code is fired...

If it can't reverse a path it does:
mov byte [currouteallowredtwoway],2 // try the best to find *any* path

Generally PBS work at signals. As you don't have a signal between the reversing of the train and the exit. The selected path is maybe not what you want.

So placeing a signal between the junction and the station would help the pathfinding process. If it fails even with a signal there, then there is really something wrong.

Or don't use PBS there ...

To atleast see what happens, post a savegame as all other do

Rob · Post by **Rob** » 26 Aug 2006 11:44

PBS is a bit strange at times.
For one it won't reserve a path to a double signal in case this is red, even if that signal isn't at the pbs junction but a few tiles further away.

Both trains, number 5 and 6 are going towards Hulst Transfer.
Train 6 takes the detour because train 5 makes the double signal (inside the circle) red. Without this double signal all the trains towards "Hulst Transfer" are taking the short cut although the PBS block would let them choose otherwise.

michael blunck · Post by **michael blunck** » 26 Aug 2006 12:39

First of all, thanks to all the experts.

@AndersI
> Sorry if I'm asking the obvious, but how far away is the next signal on the line?

Ah sorry, only a couple of tiles, see attached screenshot. It´s the one right in front of the green ET-87 which is the second train servicing that station from the south/west. This train has no Problems whatsoever.

@Rob
> Both trains, number 5 and 6 are going towards Hulst Transfer.
Train 6 takes the detour because train 5 makes the double signal (inside the circle) red.

Yes, I noticed that as well (trains don´t queue up nicely, instead they take detours). However, I don´t see any link to my problem?

@Oskar
> If it can't reverse a path it does:

Do you mean "reserve"?

In this case, the question would be why it always reserves the wrong path instead of the right on?

> As you don't have a signal between the reversing of the train and the exit. The selected path is maybe not what you want.

That´s what I don´t understand at all. The track is ending at that platform and this is the way I always link two trains to one platform. I never place an extra signal between the branch and the station entry. Why should I? Is there a deep reason to do that when using PBS?

[edit: the whole setup can be seen on this screenshot from the "picture thread": there´s a depot at the end of that track, and you can see that the path for the ET-87 going south-west is set up correctly.]

regards
Michael

Post by **Dave** » 26 Aug 2006 13:04

Maybe something to do with the depot behind the station?

Rob · Post by **Rob** » 26 Aug 2006 14:17

michael blunck wrote: @Rob
> Both trains, number 5 and 6 are going towards Hulst Transfer.
Train 6 takes the detour because train 5 makes the double signal (inside the circle) red.

Yes, I noticed that as well (trains don´t queue up nicely, instead they take detours). However, I don´t see any link to my problem?

regards
Michael

The above picture shows what I mean : the train at the waypoint "Great Pruntway Zentral" makes the double signal in front of it red, and this means the other train won't reserve a path towards "Great Pruntway Zentral" even if the train which is now at the waypoint, is further back on that piece of track. Aspecially if there are other double signals on that piece of track.
But without a savegame we can't really tell.

Villem · Post by **Villem** » 26 Aug 2006 14:44

Move the waypoint one square away from the signal, and see what happens?

michael blunck · Post by **michael blunck** » 26 Aug 2006 15:46

@Rob

the train at the waypoint "Great Pruntway Zentral" makes the double signal in front of it red, and this means the other train won't reserve a path towards "Great Pruntway Zentral"

Well, the schedule is as follows:

- train5 travels Great Prundway to the north (via the waypoint), and
- train2 (the ET-87) travels Great Prundway to the south/west

Train2 is always fine but train5 does the following all the time:

- approaches from north
- passes the waypoint
- arrives Great Prundway
- occasionally goes to the depot
- leaves Great Prundway (scheduled via the waypoint back to north)
- falsely reserves track leading to the south/west (and goes lost)

@Akalamanaia
Mmh, interesting idea but doesn´t help. See screenshot.

regards
Michael

Villem · Post by **Villem** » 26 Aug 2006 15:55

Is the signal block beyond the signal longer than 64 squares?
If it is, add a signal inbetween somewhere.

Post by **Dave** » 26 Aug 2006 16:19

Akalamanaia wrote:Is the signal block beyond the signal longer than 64 squares?
If it is, add a signal inbetween somewhere.

MB wrote:@AndersI
> Sorry if I'm asking the obvious, but how far away is the next signal on the line?

Ah sorry, only a couple of tiles, see attached screenshot. It´s the one right in front of the green ET-87 which is the second train servicing that station from the south/west. This train has no Problems whatsoever.

aahz77 · Post by **aahz77** » 26 Aug 2006 17:53

I have tried to reproduce Michael's problem by building a similar situation. It didn't occur! The northern train always went to the North. So please could you give us a savegame file for further analysis?

I noticed that the tracks with the station are not converted to pbs automatically. After I converted them manually the northern train still headed to the North, no matter if the south/western train was waiting for the station to get free or if it was miles away. The northern train always reserves the correct path.

So I suggest you post the savegame so that we can determine if there is a bug, and convert the signals back to normal to proceed playing (anyway, a junction like this with a single-track station behind it doesn't have to have pbs signals... in addition, it is not recommended to put stations into a pbs block).

Post by **Dave** » 26 Aug 2006 18:57

Have you tried deleting the tile, and rebuilding?

michael blunck · Post by **michael blunck** » 27 Aug 2006 07:16

Mmh, case closed. I´ve learnt that PBS may not be applied to stations, i.e. no station (or depot) inside a PBS block. Many thanks for your kind help.

regards
Michael

Rob · Post by **Rob** » 27 Aug 2006 07:45

Well having a station or a depot inside a PBS block isn't really a problem, you just have to know what you are doing.

For instance in the picture below I have a depot acting like a sponge if there are too many trains arriving at the station at the same time, but the depot has to ly in the direction towards the station otherwise the trains won't enter it.

DaleStan · Post by **DaleStan** » 27 Aug 2006 12:23

What Rob said. PBSing stations and depots is not an issue.

Having a junction after the station in a PBS block, however? That is an issue, since the train has to reserve something, but it doesn't know where it's going next until after it visits the station.

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