[BUG] train accident due to signalling malfunction and incautionous train driver

[Mariculous]

On the current Pak192.comic-ex testserver, the Flixtrain is continously causing accidents that will cause a deadlock.
This appeared in #124b289 (current latest)

Beware that normal gauge trains in this pakset are coded as narrow gauge and vice versa.

The exact cause of the latest accident was observed in detail:
4:45:10 Train 103 passed Lützelen Station, 41 passengers on board.
4:45:24 Train 103 enters cab signalling working mode. The signalbox successfully creates a directional reservation to the entry signal in Garbsen.
4:45:26 The signal at Nieder Sundern succesufully reseves the upcomong block for Train 100
4:45:43 First signalling malfunction in Garbsen. The tracks to Garbsen Platform 2 are reserved for Train 103
4:45:52 The malfunction was fixed.
4:46:15 The same signalling malfunction in Garbsen appears again.
4:47:14 The malfunction wasfixed again.
4:47:15 The upcoming ETCS block was cleared at (835,130), the following block was not reserved.
4:48:15 Train 91 departed at pGarbsen Westpark, signals workin correctly at that time.
4:49:10 Train 100 departed at Sundern Jungbrunnen, 29 pasengers on board.
4:49:12 Train 103 passed the ETCS stop board, and entered a block that was not reserved.
4:49:31 Train 103 passed the next ETCS stop board at danger.
4:50:11 Train 103 passed the first signal at danger
4:50:16 Malfunction at Garbsen station entry signal again.
4:50:35 Train 103 passed the second signal at danger.
4:51:53 Train 103 passed the third signal at danger.
4:52:10 Train 103 passed the fourth signal at danger.
4:52:28 Train 100 unscheduled stopped at Garbsen Westpark due to the still unfixed signalling malfunction at Garbsen.
5:52:40 Train 103 passed the fifth signal at danger.
5:52:43 Train 103 crashed into Train 100 at 107 km/h. It immediately came to a halt. Miracously nobody was hurt or killed in this accident and trains remained undamaged.

You can watch this nightly #124b289, the pakset from the following link https://www.simutrans.ovh/server/41/pakset and the savegame http://dome.xileks.de/simutrans/save/Zellikon-signalling-bug.sve
Note that the reservation tool is assigned to (small) b.

I figured out that the above was mainly by the directional reservation

[RealAmerican1776]

I didn't know there were train accidents in Simutrans.

[Matthew]

I didn't know there were train accidents in Simutrans.

It is humour.

Somewhat dry humour. I approve. 

[RealAmerican1776]

I think it gives it that realism factor. Not all railroads are perfect, while accidents are more rare today they still happen. Recently there was an accident over in Scotland that made news here in the States. Having train wreaks in my opinion could give the player something to pay more attention to in regard to signaling. We could even take some funds away from the player for lawsuits against the company though that might be over doing it.

[Mariculous]

That's true in principle, but I don't think it works quite well with simutrans principles and the way how signals work.
Given no bugs, time_interval is the only working method that can crash. Accidents are already simulated in a very basic way in that case.
Any implementation that does not unlock on its own is not suitable for an online game, where some players might prefer to check their company once a week or something like that.

Anyways, let's get back to topic please.
The above was an indeed slightly humorous description of a bug that can be observed in the attached savegame.

[jamespetts]

Freahk - thank you for your report. When you write that you figured out that the problem was mainly by the directional reservation, can you elaborate on what investigations demonstrated this? If you can describe this, you might well save a considerable amount of duplicated effort. Thank you.

[Mariculous]

Well getting rid of the directional reservation fixed all of the described issues.

[jamespetts]

Well getting rid of the directional reservation fixed all of the described issues.

Can you elaborate - do you mean simply clearing the reservation with the reservation editing tool, or do you mean changing the signalling arrangement so as to remove the ability to create directional reservations?

[Mariculous]

I just rearranged the signalling arrangement so it won't create directional reservations.
Without these, it's working without any malfuntions.

[jamespetts]

Thank you for the clarification and report. I believe that I have now fixed this; I should be grateful if you could re-test with the next nightly build.