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Another crash. Two trains leave a station at the same time, wait at the entrance of a PBS block for a train to clear, then pick crossing paths.

Crash occours on December 21st at Gawler Station.

Running alpha 48 on Windows XP.

Apparently I've fixed this already, when I load it in my a49 version they don't crash but they do in a48.

- there was road-rail junction (road owner: town)
- I removed (demolished only one, not that with rail) 4 road squares (for a bridge)
- what I see ? both rails are grayed ! (PBS-ed)
- on one of the rails train manage to run and gryed disappeared, on the second one it is still there
- there is/was no pbs signal at any side of the road-rail junction

including: savegame before doing anything,after building bridge(you can demolish bridge to see that one of the rails is still greyed until any train will pass it), ttdpatch.cfg

I'm having some more train crashes with alpha 48. They all mostly look the same, so i'm only posting one savegame, but if you want more, i've got them

Crash in a tunnel. 1 train holds up a second train at a signal in front of a tunnel. 1st train's back end clears the signal and completely enters the tunnel. As the 2nd train approaches the red light it turns green for same tunnel and crashes with train 1.

I should have posted this before, but this savegame is mad. If I load it here I get about 10 train crashes in a few minutes (with gamespeed on 8x). There is a problem with a PBS signal behind another, causing a train to get stuck (remove the first one when it pops up), but the crashes are shocking and happen at several places on the map.
It was saved in alpha 47 but still causes crashes under 48.

I have a minor problem with PBS, running Alpha 48.

In a station entrance with three lanes going to the station, when all lanes can reach any platform, PBS works as it should (blork-test1.png), but when I try to prioritize the lanes, in effect cutting off some platforms from the lower two lanes, PBS gets confused (blork-test2.png).

It seems the PBS sees that there is a free platform, activates the path finding, and doesn't find a path to the free platform and chooses something stupid instead...

Simple - Don't do that. PBS wasn't designed to be quite that smart, I think.

would be good for the future though..
"dont consider possible exits which cannot be within the PBS block.."

I've already asked for something related - "don't make it a PBS block if there are no non-intersecting paths" - but that's too hard. And this sounds like a similar programming challenge.

sobo wrote:would be good for the future though..
"dont consider possible exits which cannot be within the PBS block.."

Believe me... you have no idea how many other setups that would break. I'm trying very, very hard not to add more special cases to PBS, because those already make debugging and fixing problems incredibly hard.

Some junction setups just don't work well with PBS. This is one of them.

Patchman wrote:Some junction setups just don't work well with PBS. This is one of them.

Fair enough! (That's why I said 'minor problem')

Is there something in the PBS code that tells trains that if a train was told to skip a light and ended up intersecting a reserved piece of rail, that the rail is marked reserved incorrectly?

EXAMPLE:

Junction:

..S
<|
..S

the lines are rails, ignore the dots, the S's are signals.

A train is ALMOST out of the junction to the north, but there is a HUGE jam because of a lack of foresight on the part of the railroad's engineers (This is in my dad's current game), so the train waiting at the signal to the south is told to skip the light, even though the junction just after it still has a reserved track in it, the straight track. The train is being sent to the depot, and manages to do so safely. However, the train behind it SKIPS the light without being told to, and crashes into the train in front of it! OH NO!

Why does that happen?

AFAICT, trains just unreserve tracks once they pass them, regardless of whether or not they were previously reserved.

Yes, a train wouldn't know if the track is reserved for itself or for another train. If it comes to a tile with reserved track, it can only assume that it must be the right train, because no other train could've got to that tile, since it would've been an intersecting path.

Forcing trains to ignore a PBS signal is a lot more dangerous than with regular signals, for this reason.

Ah, that makes sense. That's approximately what I had figured happened when those trains crashed.

Interesting PBS problem here, mainly caused by stupid track layout that needs fixing by me but a problem nevertheless. The MP-54 EMU and the S2 Northern will come extremely close to crashing in this game (right in front of you when it loads) because the S2 will not reserve a path properly across the track it uses.

PBS configuration:

Under a48 this station worked fine, after upgrading to a49 this is what I get:

KaCzach wrote:Under a48 this station worked fine, after upgrading to a49 this is what I get:

agree, I noticed the same thing here ... I had to remove all PBS at stations

and I have some problems with train taking straight way at PBS junction, it takes a bit detour

KaCzach wrote:Under a48 this station worked fine, after upgrading to a49 this is what I get:

Can you explain in more detail what's wrong, and also post the savegame together with ttdpatch.cfg and newgrfw.cfg?