AI Train Speed Too Slow!

[meeshu]

Running an activity on NEC V4.

There are three AI trains used in this activity. Two of the AI trains seem to run at expected speed (as set within the consist file, and the Default performance within MSTS Activity Editor was also set at 100). But the third AI train's speed seems to slow down considerably after initially running at about the expected speed!?

At the start of the third AI train run, there is a speed limit of 15 mph which the train seems to adhere to. Then once on the mainline, the AI train initially accelerates to the speed limit of the AI train (determined to be about 34 mph by running this train/consist previously as a player), which is about 34 mph. Then shortly and abruptly the AI slows back down to around 14~15 mph, for no apparent reason!? The track ahead of this train is cleared for miles, and there is no other speed restriction along this track (I drove another test train along this track to check for speed limits/restrictions).

I can't figure out why this AI train is slowing down (so much)?

The path this AI train takes is from Perryville (MOW base) at about MP 57 and OFF the mainline. It joins the mainline at about MP 58 1/2. Then continues down to Edgewood at ~ MP 76.

There is no conflict in paths taken by this AI train and the path taken by my train. My train takes the west/north side mainline. The AI train takes the east/south side mainline. My and the AI train are both heading ~ south.

Here is the consist -

3_csx_ac4400_316_autos.zip

The locomotives used come from here.

The autoracks used come from here.

Any ideas as to why the AI train slows down suddenly?

[meeshu]

On further testing, it appears the AI train slows down immediately after reaching a signal. But despite the signal showing green, the AI train slows down. Possibly the AI train "thinks" the signal is showing "restriction"?

The signal in question is a gantry mounted one and is located at (according to MSTS Route Editor) Lat: 39.50391, Lon: -76.17812. The signal and gantry is located just before Aberdeen railway station.

The signal uses shape file ATKCPL2ABS.s, and is identified as being "ACPL 2 Head Absolute" according to the RE.

Possibly the cause of the sudden slow down might be due to signal scripting error? Otherwise, I can't see why the AI train should suddenly slow down!?

Signal script experts! Can anyone have a look at the signal script for NEC V4 and check that it is working as it should, particularly for the ACPL 2 Head Absolute signal(?)

[meeshu]

Completed some more tests.

Under MSTS, the AI train does NOT slow down when reaching the signal in question!! But, under most versions of Open Rails (stable version 1.3.1, unstable version 8th July, and NewYear MG version 67), the AI train immediately slows down upon reaching the signal!??

I've just noticed that there are speed posts just a few meters past the signal gantry. The speed posts seem to be oriented for north bound traffic (my AI train is heading south). The speed post values seem OK (125 mph for passenger trains, and 60 mph for freight trains). So I don't think these speed posts are causing the AI train to slow down(?)

So it appears that all versions of Open Rails seem to be "misinterpreting" the signal status, and/or maybe "misinterpreting" the speed post values?

Could an Open Rails developer perhaps look into this slowing train issue please?

[meeshu]

Completed even more tests!

The issue of AI trains slowing down, seems to occur ONLY for long consists (maybe 100+ cars plus locomotives) AND when the consists depart from Peryville MOW yard.

If the AI test consists are set to depart from the mainline instead right next to Perryville yard, then the AI trains run as normal and do NOT slow down!

As soon as a long AI train has cleared Perryville yard (and then accelerates) and then reaches the next clear signal along the mainline, the AI train immediately slows down to about 15 mph (again)! This has happened to AI trains that reach the signal at about MP 61.

All the above suggests that there is some signalling issue between Perryville MOW yard and the mainline signals(?)

[meeshu]

Again, ran another test train using the original consist (3 CSX AC4400's and 316 autoracks).

Some interesting results appeared! The 15 mph speed limit up the track near MP 66 seemed to appear out of no where!?

Here are some Track Monitor screenshots which might explain better what is happening.

Perryville_start (FM).jpgPerryville_first_mainline_signal (FM).jpgPerryville_cleared_MOW_yard (FM).jpg

[R. Steele]

Looks like an artifact of creating the MSTS route...nothing to do with OR and IMO nothing that OR should be concerned with correcting. If I knew more about route building and signal scripting ( no experience with either ) I'd help .... and AFAIK most people would rather work on new routes and better scripting for OR than have to spend their hobby time repairing old MSTS routes.

With your knack for testing and obvious investigative skills, you'd probably benefit from exploring and learning how to correct this problem. Of course, I could very well be on the wrong track, might have nothing to do with the route. Perhaps someone may find the time to offer some real advice/aid...be patient.
Regards, Gerry

[meeshu]

AI train speed (limits) seem to be OK outside of Perryville MOW yard. So a way around this issue is to start AI trains on the mainline adjacent to the MOW yard, as this does not present any speed limit issues (as found by testing).

Suspect there is some signalling (script) issue involved here in/around Perryville which causes AI train speed limits to show "erratic" values.

If someone skilled in signal scripts could check the signals in and around Perryville, that would be useful.

[meeshu]

Found another place where the 15 mph speed limit appears (mysteriously) on mainline track (for NEC V4 route)!

An activity I created requires collecting cars from Bayview yard and then joining the mainline just after MP 89. Speed limit is 15 mph in the yard. And mainline speed limit is 60 mph for freight.

After collecting the cars and the consist is clear of Bayview yard, the speed limit changes from 15 mph to 60 mph. OK so far. But just a bit further along the mainline, 15 mph speed limit suddenly appears! This 15 mph limit lasts for about 1/2 mile before resuming back to 60 mph speed limit. The mainline does NOT normally have 15 mph speed limits along its track, so this sudden appearance of the 15 mph limit (like at Perryville) is weird!

So something MUST be wrong with the signalling in this route!?

[Vince]

It's been 17 years and 30,289 downloads and you are the only one who has ever complained about this problem!!

If running Open Rails the log must be attached.
If running MSTS it will not be looked at. Sorry. And AFAIK, 100+ wagon freight consists were never run on the NEC.
Good luck!

regards,

[dcarleton]

When the erroneous speed limit comes up, try changing to manual mode and then back. See if that clears it.

[rman]

The Open Rails log is unlikely to reveal anything useful. Instead, what I would do is load the game up in the Visual Studio debugger and set a breakpoint somewhere in the Track Monitor code, with the goal of revealing wherever the phantom speed post or speed signal is coming from.

meeshu, could you also upload the path file you are using? That is the last piece of information needed to reproduce your scenario.

[meeshu]

Had NEC V4 route for many years, but only ran under MSTS as Open Rails was not available back then.

I don't specifically recall any "phantom" 15 mph speed limits suddenly appearing on previous occasions under MSTS. But due to limitations of MSTS and my computer back then, I only ran relatively short freight trains (no more than about 100 cars).

I run almost exclusively long and heavy freight trains on all routes now, just for fun! I don't attempt to run prototypical trains on routes. So for NEC V4 route which usually runs mostly passenger trains, I run long/heavy freight trains instead.

Did some brief test runs on the NEC V4 route at Perryville and at Bayview with some interesting results!

Under MSTS with default equipment consisting of 13 dash locomotives and 200 cements cars as a test consist in 6-200-7 configuration, the following was observed.

At Perryville, the speed limit was 15 mph and the train STAYED at 15 mph even when the train cleared Perryville MOW yard and was on the mainline where the speed limit should now have been 60 mph!?

At Bayview, the yard speed limit was 15 mph, but the Track Monitor had difficulty in deciding the speed limit between 15 mph and 60 mph for the mainline speed limit! The speed limit settled down to 60 mph, even though the train was still within Bayview yard!?

Under Open Rails (MG and unstable versions), the respective yard speed limits were correct at 15 mph, and when the train cleared the yards, the speed limit increased to mainline speed of 60 mph. However, the Track Monitor now showed that a 15 mph speed limit was just ahead of the train!? The "phantom" 15 mph speed limit had suddenly appeared on the mainline for some reason.

Here are the test paths -

15mph_test_paths.zip

It is pointless for me to examine Open Rails source code as I don't understand anything about it, let alone debugging it.

[meeshu]

So, has anyone figured out what is going on with the strange speed limits appearing?

Any solutions?