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Author Topic: [Bug] Phantom axle load limit on bridge  (Read 419 times)

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Offline Huitsi

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[Bug] Phantom axle load limit on bridge
« on: August 14, 2020, 12:14:06 PM »
Edit: Of course I solve this right after reporting it. It was a routing issue, but I would like to underline that feedback from the game me mislead me instead of helping me. In addition to the incorrect message mentioned below, for some reason the trains would route up to the bridge with waypoints, but not onto it.

This applies to the bridge stating from (355,2198) on Bridgewater-Brunel. Trains that have a locomotive with an axle load of 8t or more AND have passenger onboard refuse to go over the bridge saying the maximum is (trains max. axle load - 1t). The bridge info shows max. axle load 13t (or earlier 10t) and max. weight 175t, neither of which the trains exceed. Better bridges in the same spot have had the same issue. At the very least there is a severe communication issue, but no one on the server has come up with a good reason for this behavior.
« Last Edit: August 14, 2020, 02:54:19 PM by Huitsi »

Offline jamespetts

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Re: [Bug] Phantom axle load limit on bridge
« Reply #1 on: August 14, 2020, 05:43:45 PM »
Thank you for the report. Can I ask you to clarify in what way you believe that the feedback was incorrect? What do you believe that the feedback ought to have been in this case?

Offline Huitsi

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Re: [Bug] Phantom axle load limit on bridge
« Reply #2 on: August 14, 2020, 07:29:42 PM »
The fact that I got "maximum is 7t" message for 8t trains and "maximum is 9t" for 10t trains really confused me, although it does make sens in retrospect. Matthew also told me this kind of message could be caused by completely other issues. If that is the case, that needs to be changed. The only thing worse than no information is wrong information.

I now see that the route is checked up to the next station rather than the next waypoint. I was, however, somehow able to lead my trains up to but not onto or over the bridge with waypoints, leading me to believe the bridge was the issue.

As to what could be done about it slips into the territory of feature suggestions. First of all, if the messages can tell as what the maximum limit is, could they not also tell where it is? Secondly, a feature I have wished for in many games is a "multimeter" that would calculate and show the route between two given points.

Offline jamespetts

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Re: [Bug] Phantom axle load limit on bridge
« Reply #3 on: August 14, 2020, 09:26:16 PM »
Thank you for your reply. I am still somewhat confused as to what exactly was unclear about the original message. Was it in fact incorrect about the weight limit in question? If so, I will need a reliable reproduction case to be able to look into this.

Offline Huitsi

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Re: [Bug] Phantom axle load limit on bridge
« Reply #4 on: August 15, 2020, 09:47:24 AM »
I don't think the messages were wrong. The was just a series of coincidences that lead me to misdiagnose the issue. As for the messages possibly being wrong in other circumstances, I don't have a reproduction case as I heard that from Matthew.

Of course, had the messages just pointed at the first problematic tile I would have immediately noticed the trains we're trying to go somewhere they weren't supposed to.

Offline freddyhayward

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Re: [Bug] Phantom axle load limit on bridge
« Reply #5 on: August 15, 2020, 09:59:46 AM »
I found that when my coaches were too heavy (in weight, not axle load)  for an elevated road, it was reported as an axle load problem. Though I'm not familiar with the code, I suspect that the error is triggered by attempting to find an alternate route through an axle-load limited road.

Offline jamespetts

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Re: [Bug] Phantom axle load limit on bridge
« Reply #6 on: August 15, 2020, 11:05:19 AM »
I found that when my coaches were too heavy (in weight, not axle load)  for an elevated road, it was reported as an axle load problem. Though I'm not familiar with the code, I suspect that the error is triggered by attempting to find an alternate route through an axle-load limited road.

That is entirely possible - there is no algorithm with a reasonable degree of complexity that is capable of distinguishing which of multiple possible routes that a player needs to be informed about.

Offline freddyhayward

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Re: [Bug] Phantom axle load limit on bridge
« Reply #7 on: August 15, 2020, 11:54:35 AM »
That is entirely possible - there is no algorithm with a reasonable degree of complexity that is capable of distinguishing which of multiple possible routes that a player needs to be informed about.
Since that is the case, then it is probably best not to send these alerts, since they mislead the player into thinking that that problem occurs in their route when in reality it only occurs in a potential route.

Offline Freahk

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Re: [Bug] Phantom axle load limit on bridge
« Reply #8 on: August 15, 2020, 09:15:17 PM »
That is entirely possible - there is no algorithm with a reasonable degree of complexity that is capable of distinguishing which of multiple possible routes that a player needs to be informed about.
There is a quite simple one:
If no route can be found, reroute with a dummy vehicles:
1. no weight, but vehicles actual axle load
2. no axle load, but vehicles actual weight
3. no weight and no axle load but with only exactly one prohibitive? constraint (I do always confuse these)
Finally, iterate the routes again checking for the ignored restriction, so we can give preciese feed back to the user, something like "No route was found, At (x1,y1), the maximum axle load would be exceeded. At (x2,y2) the maximum weight would be exceeded. At (x3,y3) the constraint ... would be required."
Well or something like that.
Seems rather simple and incredibly more useful to players, especially as we can that way tell them where exactly the issue is, instead of "there is an issue somewhere"
Practically, we would cancel at the very first obstacle on the way and output that single location, instead of posting a huge list of koords.


Edit: Oh, I can confirm that low bridges on the route of a short stage coach will cause "...The vehicles axle load is 1t, but the maximum is 0t" error messages, which is extremely missleading.
That doesn't seem to be generally the case and I have no idea when exactly that message will be displayed.
« Last Edit: August 15, 2020, 10:35:04 PM by Freahk »