AI is slowing down for...nothing?

[nicky9499]

Hey guys,

I've got this strange issue on some parts of my route, wherein AI trains inexplicably slow to speeds of 15mph for no good reason. There's this part where double tracks become triple and I've not put up any 15mph speed signs around there, but even when I'm driving the speed limit drops to 15mph for like, I don't know, 50 feet?

Then there's the another stretch with a nice, straight 55mph run, a station at the end, and 40mph through dense residential. For some reason the AI finds it hilarious to crawl past the station at walking pace. It's a standard 1-track AJS invisible platform. This crawl-through-the-station only happens to a few stations of no obvious reasons as to why so and there is no "ghost" speed limit reduction.

How can I fix this inconsistent, unrealistic and annoying phenomenon?

Regards,
Nicholas

 

[Dermmy]

The AI never slows down for 'nothing'. It slows down for a reason. Finding and rectifying the reason can be a long frustrating process.

My first check is always signal placement and default lever positions. Sometimes a lever needs to default to the intuitively wrong direction. What messages are you betting from mouse-over on the signals?

Next question would be what driver commands are current? Drive/Navigate to/via, the four possible combinations just there will often yield very different results. Is the station industry-active? If so delete it temporarily and see what happens.

Trial and error, trial and error. On my current WIP route I spent about a week (and for me that's 20 or 30 hours) trying to get the AI to run several trains through a branch-to-main wye without standoffs or SPADs. I have no idea how many track, signal and lever combinations I tried. But guess what? It works....

 

[nicky9499]

In the first scenario the signal is either a clear or diverging medium, in which case the limit should still be 27 instead of 15 (on a 55 track).
In the second scenario the signal is clear. The AJS platform is a simple passenger-interactive asset. In both cases the "Drive To/Via" command is used. Turnouts are all aligned for the main. It's all puzzling because I'm doing everything that is logically correct.

Sometimes a lever needs to default to the intuitively wrong direction.

This is an interesting proposition. I've just tried it and the situation kind of gets worse. Instead of realigning the (automatic) switch, erm...automatically, the AI stops completely, gets his virtual conductor to throw the (automatic) switch, before continuing on his way.

 

[Dermmy]

If you are using the Drive TO command, then you are specifically asking the AI to stop. If you want the AI to not slow down ,try the 'via' commands. If your problem is in TS10 or 12, the 'Navigate' commands may give better results than 'Drive'. If you are in 06 stick with 'Drive'...

 

[nicky9499]

The "to" commands are usually only for passenger trains which call at stations. For all other trains that do not stop their instruction strings are just a series of "via" commands. Irregardless, the slowing down issue affects all trains, even player-controlled ones. There appears to be an invisible 15mph limit for 50~100ft and any train with computerized protection will dump the air when the train blows through at line speed. In the case of AJS stations - even after replacement - there's is no invisible speed limit, but AI trains still insist on crawling through at walking pace.

I also read somewhere using "navigate" increases the AI's propensity to start doing funny things (like getting creative and finding some other stupid route, hence "navigate") when a red signal is encountered, instead of sitting there patiently. Is this true?

Nicholas

 

[Dermmy]

...Is this true?

Nicholas

Ask two people that and expect at least three answers!

There are a myriad factors influence the AI and how it performs and truly every situation is unique. Well that's not quite true either, once you figure out why Problem 'A' happens at Place 'Z', then applying the solution to every similar place should prevent the same issue from recurring.

The problem with all these "Why does the AI do this....." threads is that the question is almost unanswerable. Lots of folks will chime in with the goof-proof fix that sorted a similar issue on their route. Whether or not that is a fix for you - well probably not. Even whether it's a guide to point you in the right direction is not guaranteed.

I have a couple of big routes that run as well as can be expected - and by that I mean pretty much goof-proof - under total AI control using vey very simple driver command chains. But that's my routes signalled my way, and the same thing won't necessarily work on other routes. Or in other versions of Trainz. And signalled my way really means signalled the AI's way, because I don't necessarily always like the way my routes are signalled and I definitely don't always like the way some of my track is configured (that wye mentioned above is a case in point!). But after about 8 years of doing this Surveyor thing I have a pretty fair idea of what the AI expects and how it will interact. You can't teach (or learn) that in a forum post.

Change things. "Save As". Run it. If it's better keep the change, if it's the same or worse bin the change. I'm pretty sure that your issue is signal and/or lever placement, but without a bucket load of screenshots and possibly even running the route there is no quick "Change This...." answer.

And back to the original question - on a TS10 route signalled the way the AI expects it to be signalled in my opinion 'Navigate' beats 'Drive' hands down. But I almost guarantee you that the next post will tell you not to use it - not ever -

 

[carr]

One thing I have found to work, it to put a track marker just before each of the stations which maintains the speed of the train also make sure any approach signals which are close, are behind the the marker. You should name these markers and tell the train to go via the marker and not the station. However depending on the distance from the station that you place the marker you may find a slight speed reduction depending on the station being used, say 130KM to 90Km as it runs though.
Hope you find this useful as it works for me.

 

[nicky9499]

Hi Andy,

Thank you for the detailed explanation, I do understand. The automated session runs well (hands off) most of the time, which is good enough as I've got other issues on my Trainz plate. When it goes out, perhaps brighter minds running the route will figure out a solution not yet discovered.

One thing I have found to work, it to put a track marker just before each of the stations which maintains the speed of the train also make sure any approach signals which are close, are behind the the marker. You should name these markers and tell the train to go via the marker and not the station. However depending on the distance from the station that you place the marker you may find a slight speed reduction depending on the station being used, say 130KM to 90Km as it runs though.
Hope you find this useful as it works for me.

This sounds good, I'll try it later.

Cheerio,
Nicholas