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Simutrans Extended => Simutrans-Extended development => Simutrans-Extended bug reports => Topic started by: Ranran on March 10, 2019, 11:17:31 AM

Title: Strange reorder of freight train
Post by: Ranran on March 10, 2019, 11:17:31 AM
Wagon may carry out strange reorder when it reversed.

Place the brake van right after the locomotive and at the end of the train like this.
(https://i.imgur.com/b4U9MIx.png)

(https://i.imgur.com/UFSyBJ4.gif)

In this example, reordering the brake van should be unnecessary.
However, It will reorder some times and the two brake vans will move to the middle of train. And never comes again to the end. (´・ω・`)
Title: Re: Strange reorder of freight train
Post by: jamespetts on March 10, 2019, 11:30:59 AM
Thank you for your report. Can you upload the saved game that you used for testing?
Title: Re: Strange reorder of freight train
Post by: Ranran on March 10, 2019, 11:55:50 AM
Yes, here it is (https://drive.google.com/open?id=1cckw4TvbAPIZYL2fnHiZAcJdXtkhJw-Y).
Title: Re: Strange reorder of freight train
Post by: Ranran on April 27, 2019, 07:20:42 AM
For your information
(https://i.imgur.com/vDWphpE.gif)

I am now testing a patch that shows the formation of the train.
Since I have not changed the re-order algorithm, the reorder behavior is the same as the release build.
This will help to review the reorder algorithm.

EDIT:
This type of freight train formation (make wagon a sandwich with brake van) does not require a brake van rearrangement if the direction of travel changes, such as a switchback.
For this reason, this is the composition of freight trains often found in the 20th century Japanese countryside. (Currently extinct by motorization)

(btw, this is still a draft version so car's no will be fixed....(´・ω・`))

EDIT2: distinguished wagon by color
(https://i.imgur.com/YhuGkCl.gif)

(https://i.imgur.com/VBaGRV7.gif)
Title: Re: Strange reorder of freight train
Post by: jamespetts on April 28, 2019, 03:31:03 PM
Thank you for that. It is difficult at present to work out whether it is sensible to work on a basic fix now or put somewhere in the truly gargantuan list of tasks needing to be done (on which no progress has been made since early 2018 because all the time has been spent fixing bugs) a more fundamental recoding of how this system works.

Edit: For reference, I should note that the straightforward option would involve accommodating new specific cases; anything more general or abstract would require a major rewrite. If anyone else would like to do this, of course, that would be most welcome, but we would need to discuss in some detail how that would work.
Title: Re: Strange reorder of freight train
Post by: Ranran on April 30, 2019, 10:19:16 AM
I think this needs to be fixed at least when implementing recombination system.
If the vehicle formation is broken in an unexpected order when convoy returns back from the terminal end, it will cause great confusion in the next schedule(e.g. separation of two convoys).
Vehicles that should originally be in convoy A may be included in convoy B.

However, if you ignore the strangeness of recombination, the design of the recombination system may absorb inconsistencies.
e.g. The misplaced vehicle is teleported from Convoy A to Convoy B.
But it will disappoint players who enjoy watching the train. (´・ω・`)