Tunnel track renewal

[killwater]

Around the 1916 when the track inside the rail tunnel is renewed it is broken - the trains cannot find the route through it. After replacing the track manually it works again.

[jamespetts]

Thank you for your report. I need some more information to understand this issue properly: with what track is the track in the tunnel replaced such that trains no longer pass over it properly? It will also help to have a saved game in which this issue can reliably be reproduced.

[killwater]

Ahhh unfortunately I do not have this tunnel anymore. I may be able to try to recreate it tomorrow.

[jamespetts]

Please do - that would be very helpful.

[killwater]

http://simutrans-germany.com/files/upload/1.sve

Let the little monster run for a few loops and then you can see the faulty replacement. Shouldn't take more then a minute.

By the way does the track wear depend on the speed of the convoy?

[jamespetts]

Thank you for this report: that is helpful. I have now pushed a fix for this, but, because this is a somewhat complex issue, the effect will not immediately be obvious in the saved game that you sent because the information encoded in the tunnels (i.e. the replacement track) is incorrect, which should not occur in the future.

What you are seeing was caused by a combination of three separate problems. The first was that, when tunnels were built, the tunnel's own maximum axle load was used instead of the lesser of the tunnel's and the way's. Renewal, however, worked correctly: the minimum of the two was used. I have now fixed this, but this will only apply to tunnels built after the fix was applied.

The second problem was that the tunnels had their own ways defined in order to give way graphics that looked like the inside of tunnels. This is a system inherited from Standard which does not work well in Experimental because of the progression of weight limits through the ages: types of tunnels would last much longer than types of track, with the result that the type of track built automatically with an older type of tunnel (such as the brick faced example here) would be the latest type of track from the 1840s, with a maximum axle load of about 10t, which is useless in the 1910s. This problem, however, was masked by the first problem - until the time came for renewal. I have dealt with this by disabling this in the pakset for new tunnels for the time being (existing tunnels will not be affected). The only way to make these tunnel internal graphics work properly is to have them as a separate thing from the way graphics, and that would require some considerable amount of coding work, which is something that I should like to do, but it has to join a very long and slow moving queue of higher priority items. The graphics are ready for when I get around to this, however, or when somebody else encodes this.

The third problem was that, on renewal, the specific tunnel tracks could not be selected, and so the ways were replaced by a normal type of track with the specifications nearest to the type of track (i.e. the tunnel track) being replaced, in this case, the 95lb/yard track. Because the first problem does not apply to renewal, the correct axle load for the 95lb/yard track would be set, and the track in the tunnels would no longer be able to take the Brighton Baltic locomotives that you had set up for this test to run through the tunnels.

So, in future, a standard type of track should be built with the tunnels, and any renewal should be to this or a better type of track available in the future if that type of track becomes obsolete. Tunnels should thus not downgrade to a lower weight limit in future in the way that they do in this example - but this cannot affect tunnels already built because the renewal way is already saved into the game, as is the maximum weight for each tile of track.

[killwater]

Thank you James. That is a nice and detailed answer. Please note though that no train could enter the tunnel at all (before the fix at least). If I remember correctly even the lightest  one (just one small loco) did not work. for
Just one question regarding the tunnel max axle load - why do we even need it? I do understand the max axle load for the given type of track but for the tunnel type? This would rather be dependent on the geology rather then the lining material.

[jamespetts]

As to the problem where nothing would enter the tunnel at all, I was not aware of this as an issue. Can this be reproduced with the fixed version from a fresh saved game?

As to your question, to some extent, this is a remnant of the way in which things worked in the past, but it is certainly possible (I think) that a certain type of tunnel might have some maximum axle load restriction. It would take more work than it is worth to remove it at this juncture.

[killwater]

Tested with:
Simutrans-Experimental_161004_52e826d build from http://server.exp.simutrans.com/Devel-new-builds/ still does not work. I replaced the tunnel with a new one.

[jamespetts]

When you say "still does not work", can you describe exactly what you mean? Also, is that a binary of the latest devel-new-2 commit?

[Ves]

When you say "still does not work", can you describe exactly what you mean? Also, is that a binary of the latest devel-new-2 commit?

I confirm that that build is devel-new-2 from the commit starting with 52e826d. Incidentally, I only upload compiles from the devel-new-2 branch, despite the folder still is called devel-new-builds (without the "-2")

[killwater]

It means that even a very light loco does not find a route through the tunnel after renewal.

[Junna]

I assume this is where tunnels were renewed as tube tunnels when they were in fact full-size tunnels, as I reported previously?

[jamespetts]

It means that even a very light loco does not find a route through the tunnel after renewal.

Does this mean that the displayed maximum axle load of the track after renewal does not match the maximum axle load as appears to be applied in practice? If so, I should be grateful if you could upload a saved game of tunnel track in this state so that I can track down this problem.

Edit:

I assume this is where tunnels were renewed as tube tunnels when they were in fact full-size tunnels, as I reported previously?

I think that I have missed this report - can you point me to it?

[Junna]

[/b]I think that I have missed this report - can you point me to it?

http://forum.simutrans.com/index.php?topic=15756.0

[killwater]

A1X Terrier cannot enter the tunnel:

http://simutrans-germany.com/files/upload/1.sve

[jamespetts]

Thank you for that: the problem appears to have been that the track was being replaced by tube tunnel track, which had additional way constraints stopping the other trains from using it. I have fixed this now by requiring the renewal code to use track with no more restrictive way constraints than that being replaced.

In any event, I think that I have fixed this; do you care to re-test?

[killwater]

Seems to work fine. Thank you

[jamespetts]

Excellent - thank you for testing.