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Thread: Unrealistic AI Train Speed!?

  1. #1

    Question Unrealistic AI Train Speed!?

    Doing AI train tests and found that AI trains seem to go much faster than in the case where the player drives the same trains!

    For example. One consist I've found does up to around 65~70 mph when run as an AI train (when compared to a driver train pacing the AI train). But driving the same AI consist later as a test, the maximum speed is only around 31 mph!

    Here is one consist which seems to have considerable speed differences when comparing AI speed and driver speed.

    2_up_44ac_397_mt_coal.zip

    Possibly the AI trains do NOT have realistic physics applied to them, which allows them to run faster than expected?

    Or what?

    This higher than expected AI train speed spoils reality and makes activities difficult to create and run.

  2. #2
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    I wanna say that this issue has been brought up before but can not remember where. The unrealistic speed is also there if you are driving a consist and switch to autopilot as well. Example on the Mullan Pass route, when operating the Horsepower Hour activiity, the best I can do up the pass is 12-13MPH but when in autopilot, the train is about 1.3MPH slower than the posted speed which starts at 45MPH at the bottom and 20MPH at the top.

    Sent from my SM-G988U using Tapatalk

  3. #3
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    AI and autopilot do not use the same physics set as the player. Both will accelerate up to the max permissible track speed, or max allowed consist speed as set in the consist file. as soon as possible. The player on the other hand has to deal with all of the natural laws of physics as determined by the OR code and applied to the player consist. Trying to compare AI and Player is like comparing a Ford Mustang with an 18 wheel rig.
    Beer is not a matter of life or death, it is much more serious than that.

  4. #4
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    Quote Originally Posted by baldwin View Post
    AI and autopilot do not use the same physics set as the player. Both will accelerate up to the max permissible track speed, or max allowed consist speed as set in the consist file.
    So in theory --- paying attention to the emphasized above --- if you have dedicated consists for a specific OR profile that contains one route or routes of comparable speed limits...you can adjust all the AI consist files to match max route speed or realistic speed as you prefer? Does this work in practice?
    Cheers, R. Steele [Gerry] It's my railroad and I'll do what I want! Historically accurate attitude of US Railroad Barons.


  5. #5

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    Comments noted, thanks.

    Yes. It was as I suspected, that the AI trains do NOT conform to physics as do player trains, unfortunately!

    So to limit AI train speed, one might have to edit consists maximum speed (temporarily) to make it more realistic.

    Is there no other (quicker or easier) way to limit AI train speeds?

    For Open Rails developers!? Can they perhaps enable an option to limit AI train speeds to more realistic ones?

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    Quote Originally Posted by meeshu View Post
    For Open Rails developers!? Can they perhaps enable an option to limit AI train speeds to more realistic ones?
    That's been discussed many many times, here and at ET...if I remember correctly it comes down to resources available to compute everything...the load on individual users might be unsupportable...please, do not rely on my explanation, look through the threads for a more reliable answer from one of the developers. There were some other reasons -- perhaps with AI traffic management -- that were involved.
    Cheers, R. Steele [Gerry] It's my railroad and I'll do what I want! Historically accurate attitude of US Railroad Barons.


  7. #7
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    Quote Originally Posted by R. Steele View Post
    So in theory --- paying attention to the emphasized above --- if you have dedicated consists for a specific OR profile that contains one route or routes of comparable speed limits...you can adjust all the AI consist files to match max route speed or realistic speed as you prefer? Does this work in practice?
    Quote Originally Posted by meeshu View Post
    Is there no other (quicker or easier) way to limit AI train speeds?
    You could either set the consist speed or use the maximum speed command in timetable mode. But either way, the speed limit would be applied over the length of the entire run, so it would still not quite be the same as having the full physics simulation. For activity mode, I believe there is also an "adherence" value that defines how fast the AI drives with respect to the line speed limit.

    Quote Originally Posted by meeshu View Post
    For Open Rails developers!? Can they perhaps enable an option to limit AI train speeds to more realistic ones?
    No, because...

    Quote Originally Posted by R. Steele View Post
    ...if I remember correctly it comes down to resources available to compute everything...the load on individual users might be unsupportable...
    It would too resource-intensive to simulate the physics for every AI train, so we have to fake it. Note that every train simulator does this - RailWorks, Train Sim World, Run 8. Except for OpenBVE, of course, which doesn't have AI...
    Ryan
    US-based railfan and programmer. Author of various timetables and safety scripts for Open Rails.

  8. #8
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    On another note altogether, if you simply want to hard code speeds in to your AI trains:
    Open the consist file and look for this line: MaxVelocity ( xx.xx x.xx )

    Change the values in the below MaxVelocity lines to create a reasonable facsimile to the speeds listed on the right (min/max)

    MaxVelocity ( 12.34 0.50 ) 10:20
    MaxVelocity ( 12.34 0.75 ) 15:20

    MaxVelocity ( 18.50 0.50 ) 15:30
    MaxVelocity ( 18.50 0.75 ) 22.5:30

    MaxVelocity ( 24.60 0.50 ) 20:40
    MaxVelocity ( 24.60 0.75 ) 30:40

    MaxVelocity ( 30.80 0.50 ) 25:50
    MaxVelocity ( 30.80 0.75 ) 37.5:50

    MaxVelocity ( 37.00 0.50 ) 30:60
    MaxVelocity ( 37.00 0.75 ) 45:60
    Neil

    Here at home, in the railroad mayhem capital of the world.

  9. #9

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    Very useful information! Thanks!

    Editing the parameters under MaxVelocity does limit AI train speeds. Also, changing the AI train Default performance value in the Activity Editor also changes/limits AI train speeds as I've just found out.

    The downside to this is if wanting to drive any AI train, the train speed will be limited to that value edited previously in MaxVelocity and/or in Default performance. So the AI train MaxVelocity and/or Default performance values may have to be restored to their original pre-edited values if wanting the trains to perform to original speeds.

  10. #10
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    Just one small point. No matter how fast you set the consist max speed to, when running as AI it WILL conform to the various track speed limits, so if you have the consist speed set at 75mph maximum, but track speed is only 30mph, the train will run at 30mph.

    The problem is not one of consist maximum speed, it is the unrealistic acceleration and braking plus the ability to maintain track speed while moving up grade with a heavy load.
    Beer is not a matter of life or death, it is much more serious than that.

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