Reservation bugs seem to have resurfaced

[Junna]

The former bug with reservations not saving correctly when on a route with waypoints appear to have resurfaced in the latest 11.x, at least since quite recently.

[jamespetts]

Can you give instructions to reproduce?

[Junna]

Cannot reproduce it easily... A ring route seems to give the result most easily - when loading (mostly from a restart of the game, but I am not sure) a train will occasionally have reserved space that is already occupied by another train, resulting in all grinding to a halt.

I am not sure this is the same as the other error, which behaves the exact same way as the old reservation bug (where waypoints would make the train run into another one and get stuck on a long route upon loading), on existing save games it repeats in the same areas as that one, but I cannot reproduce it easily in a way that takes less than a few hours; but any large station with many trains going into the same platform ought eventually to display it (viewing the block mode, it will display oddities occasionally, like blocks not reserved where there is a train present and occupied by the wrong train, etc.)

[jamespetts]

Can you upload a saved game in which this issue is present? It's not really practical to debug a hit and miss problem starting from scratch without knowing the circumstances in which it can and cannot be reproduced.

[jamespetts]

Is there any recurrence of this in 11.2?

[Junna]

It would appear so. If you look at Reddmere on the server game, it has happened, causing massive jams on AEO's goods services.

[ӔO]

that was jammed in 11.1, actually.

I'd fix it if I could...

[jamespetts]

Yes, this occurred before 11.2, so this is not a known occurance in 11.2. I have now reset AEO's password, so hopefully he should be able to gain access now.

[ӔO]

https://dl.dropboxusercontent.com/u/17111233/client3-network.sve

at 249,697, the coal train follows the oil train when it should not.

[Carl]

There are still some reservation bugs related to platforms in 11.2. (Posting here since my earlier thread was moved to solved.)

The nub of the problem is this: When a convoy only occupies a small proportion of a long platform, it is possible for another convoy to enter the platform behind it. This can arise in very specific situations like the following:



There are two convoys waiting in the second-to-left platform. This is an unresolvable situation, since the rightmost convoy wants to reverse and head west out of the station, and the left-most convoy wants to carry on east out of the station. This bug arises as follows:

Since the right-most train is reversing here, it waits at the far end of the platform and only reserves two tiles. The convoy "waiting for clearance" is a through train and as such stops at the middle of the platform. It has been given clearance because the middle of the platform was empty -- only the far end is reserved for the rightmost convoy.

This is, I think, not related to a bug in reservation behaviour per se but rather is an oversight related to the recently-added behaviour where "through" trains will stop at the middle of platforms. The problem only arises because reversing trains retain the old behaviour -- they stop at the far end of the platform. In order for these two behaviours to coexist without problems like the above, there needs to be some mechanism for a train to block out the entire platform it is occupying -- at least, if it intends to reverse.

[waerth]

I have similar problems on my network of trams. Basically when running more than one tram on a line with signals and passing loops will grind down the whole line after a month of playing time with all trams waiting for eachother.

Running more than one vehicle on a line seems impossible now.

11.2

W

[waerth]

My savefile is 50 mb. Am currently busy uploading it to my personal webspace, will add link here when finished (in an hour or so)

Should be easy to see as I was just in my second month of the game. It is the one line with multiple trams stalling near one end of the line. It looks messy as I was making spurs to manoeuvre the trams to which only worked to some extend.

W

[waerth]

The link to the savefile (close to 50 mb!) http://46.4.228.234/~walter/gwnn/www1890.sve

[jamespetts]

Wearth - thank you for uploading that. There is a very odd arrangement with the tram on the main line to the left - what exactly is supposed to be happening with that? It is not clear what the intended behaviour is here.

[waerth]

Like I said I rearranged the tracks extensively to get the trams to move again.

Basically it is the tram named: (4) Tram Dolford<>Kisingport C

That is blocking all of it. It is supposed to go to Kisingport Centrum and was waiting at a piece of double track for permission to go on. But after the tram that was coming from Kisingport passed the signals there the tram C did not move as it should have and kept on waiting for permission. So all the trams after it got stuck and I frantically started rearranging the tracks to get trams moving again.

Maybe I should have given you a save before my re-arranging the whole lot!

W

[jamespetts]

Do you still have that earlier save?

[waerth]

No,

But I have just made a new one. I am sending all of the trams home to the depot and they pile up again at one piece of double track. I can upload that if you want. Will take me an hour or so.

W

[jamespetts]

If you could upload a saved game in which the problem is about to happen rather than in which it has already happened, that would be very helpful indeed: in the latter case, I cannot actually reproduce the problem occurring, which is necessary to track it down.

Thank you.

[waerth]

Well the other savegame is uploading now. I hope it will help. Expect a link in about an hour or so.

W

[jamespetts]

Thank you.

[waerth]

Ok last savegame. Let me know if it didnt work as the upload stuttered once while uploading. But the filesizes match.

http://46.4.228.234/~walter/gwnn/PileupWaerth.sve

[jamespetts]

Hmm - I am not seeing all the trams piling up in one place here. The only error that I can find is that one tram seems to ignore signals until its schedule window is opened and closed. On what tile were the trams getting stuck?

[waerth]

Ok, just restarted the game myself and the trams started moving.

I had this same thing a number of versions ago. That the underground tracks would not be recognized untill I saved the game and then restarted it. This seems to be the same thing more or less.

It went away in later versions of experimental so I hope that will happen again now. For now I will just save and reload :/

[jamespetts]

Hmm - odd. I am currently investigating several block reserver bugs, so it is possible that this might be fixed incidentally when I fix those.

[jamespetts]

I have now fixed several reservation bugs on the 11.x branch. I am not sure that I have found them all, but it is a start at least.

Carl, as to the issue that you have identified, that is a very tricky one to solve, and would probably require somewhat fundamental changes to the signalling to fix fully. Such changes are desirable eventually, but are not the highest of priorities, I am afraid. (The ultimate solution would be for a route always to reserve to the next signal even if there is a station first, getting rid of the implicit signals in platforms).

[Carl]

Hi James, thanks for the reply. In many cases errors like the above can be avoided by more precise platform management. However, any usage of choose signals at stations with a mixture of through and reversing services is currently liable to lead to these blockages -- perhaps this should be flagged up somewhere as a practice to be avoided for the time being.

[waerth]

Hi let me try to describe what is happening. Basically the problems only happen when I add either new signals or new track and send existing trams over it.

For instance this is my current track (s = signal, <> are directions)
                _S_____>_______S_
------------/_S_____<_______S_\-------------------

Now if I add new signals in like this to create an extra space for the trams/trains to use:

                _S_____>__S_____S_
------------/_S_____<__S_____S_\-------------------

Basically al Trams grind to a halt at the new signal and refuse to go on untill I save the game and reload the game. Same thing happens if I extend the passing track, making it longer.

Also if I extend existing track by adding a new part to it, trams (and I presume trains also) will refuse to use the new track until I saved and reloaded the game.

Many many many versions ago I had the same with underground tracks. Aboveground everything would run normal but underground if did any "editing " to the lines I would have to save and reload  the game. I then quit simutrans for 6 months or so as it is a very frustrating way to play and when I downloaded a new version the behaviour was gone. Never know if it once was a bug or not.

W

[jamespetts]

Thank you for the description, Wearth: that is helpful. May I ask - does this occur on the latest version (11.3)? Do the vehicles become unstuck if you open their schedule windows then close them again?

[waerth]

Do the vehicles become unstuck if you open their schedule windows then close them again?

Nope

It is version 11.2 still. Did not want to download 11.3 as I saw other problems reported in that one. If you want me to try with 11.3 I will do so off course.

W

[jamespetts]

11.3 contains a number of fixes for reservation issues, so I recommend that you try with this version.

[waerth]

Unfortunately it doesn't seem solved. The screenshot shows the tram waiting in front of the newly added double track section. And it is waiting for clearance. And will not move! Not even after the other approaching tram has passed it! It will simply not go anywhere, unless I save and load.

[jamespetts]

Hmm - I am struggling to reproduce this. Can you give me a saved game in which this can be reliably reproduced, and instructions as to how you managed to reproduce it reliably? That would be very helpful.

[cousjath]

I'm having this bug too. After a train has gone past somewhere, sometimes it remains as being reserved by it. This occurs after I had a passing loop/signals, but not always. I think it after I've added a passing loop where the next train will have to go onto the other track, but I'm not certain. The track remains reserved even if I click on the convoy that has the piece of track reserved and change its schedule.

I can clear the track of the reservation by doing one of the following:

• Sending the convoy with the reservation into the depot. After it enters the depot, it loses the reservation.
• Deleting the track with the reservation and relaying it.
• Saving the game and reloading.

I had this problem in 11.0. I've just tried out 11.4 and had the same thing happen.

[jamespetts]

Thank you for the report (and welcome to the forums - I see that this is your first post). I have had, as you will have seen from above, some trouble reproducing this error on my computer, which I need to be able to do in order to fix it, so I am going to need to try to narrow this down somewhat. Does this occur on double track with signals in each direction, or does it only occur on single track sections with passing loops? Are there any circumstances in which this can be reproduced reliably? If so, as precise a description as possible of them would be very helpful. Thank you!

[ӔO]

The rail convoys don't update their path immediately when track layouts are changed, so block reservations need to be cleared a few times to force update their paths.


The other reservation bug is the one carl pointed out with trains not keeping their reservation inside stations when they are about to leave.