Wheelslip problem appears after T:ANE SP4 update

RobKi

Member
A favourite railcar which used to run without problems in T:ANE SP3 seems to have acquired heavy wheelslip sensitivity in SP4.

The item in question is the very nice <kuid2:35848:80130:4> German VT98 06, by sg1 plus Heinz Schubien and Brummel.

I run this under manual control in realistic mode on level track, hauling nothing, brakes fully released. Throttling up to notch 1, the car departs, but immediately the yellow wheelslip indication starts blinking. No other vehicles display similar wheelslip behaviour. It continues blinking even when I trottle back to 0 and the car rolls on by its inertia.

Has something changed between SP3 and SP4? Is there a global setting which I may have inadvertently changed? Is there anything I can change, for example in the config file, to make the wheelslip effect on this car more realistic (or switch it off altogether)?

Any help would be appreciated.
 
Look, there must be somebody out there on this forum who can give me a few shouts in the right direction.

Where do I look? In the engine specifications? No variable called 'wheelslip' to be found there. Do I have to tinker with 'adhesion'? Or 'moving-friction-coefficient'?

And if I'm asking a stupid question - How do I change wheelslip sensitivity to a more realistic value - then don't hesitate to tell me. Not getting any reaction is slightly frustrating, and quite unlike my pleasant experiences on this forum so far.
 
It is quite common that old standard enginspecs suffer from such behavior. And I understand fully N3V bussiness plan to use as much chances as possible to turn everybody to TSR19, thats why they probably made the rules for running older engine specs more strict in latest SP instead of repairing old bugs. If You would like the railcar to run as in real, You need to find/create the engspec made according latest standards for Your favorite car type anyway.
 
It is quite common that old standard enginspecs suffer from such behavior. And I understand fully N3V bussiness plan to use as much chances as possible to turn everybody to TSR19, thats why they probably made the rules for running older engine specs more strict in latest SP instead of repairing old bugs. If You would like the railcar to run as in real, You need to find/create the engspec made according latest standards for Your favorite car type anyway.

The engine-specs are created by the content creators and the base specs were changed in TRS2009 and TC3 (actually started here in TC3). If the asset was from an earlier period, then the spec needs updating. Over the years, the program engine has changed, and there are probably other changes done in SP4. I don't remember if they can be changed on the fly as they can be in TRS19, but if so that might be an option to find out what's up with the asset.

If anything, I would submit a bug report and let someone from the QA Team contact Rob and work through the problem. They're good that way and have assisted and even report back what the resolution of the problem is if there is one.
 
Thank you, JAGG and John. I understand that the problem may be due to the railcar being an older item; it is listed on the DLC as Build Version 3.5.
I have submitted a bug report and will let you know here how the story unfolds.
 
A favourite railcar which used to run without problems in T:ANE SP3 seems to have acquired heavy wheelslip sensitivity in SP4.

The item in question is the very nice <kuid2:35848:80130:4> German VT98 06, by sg1 plus Heinz Schubien and Brummel.

I run this under manual control in realistic mode on level track, hauling nothing, brakes fully released. Throttling up to notch 1, the car departs, but immediately the yellow wheelslip indication starts blinking. No other vehicles display similar wheelslip behaviour. It continues blinking even when I trottle back to 0 and the car rolls on by its inertia.

Has something changed between SP3 and SP4? Is there a global setting which I may have inadvertently changed? Is there anything I can change, for example in the config file, to make the wheelslip effect on this car more realistic (or switch it off altogether)?

Any help would be appreciated.
I didn't see much difference in the VT98 06's behavior between SP3 (94616) and SP4 (105766).

Thank you, JAGG and John. I understand that the problem may be due to the railcar being an older item; it is listed on the DLC as Build Version 3.5.
I have submitted a bug report and will let you know here how the story unfolds.
Rob, I played around with the VT98 06 railcar yesterday and started writing up something last night on it but didn't post as I'm looking for a confirmation about the exact meaning of the flashing throttle indication for locos with kind "engine" especs - I didn't find what I was looking for yet however here's what I wrote:

I put the VT98 06 on a 1 baseboard single loop of track. In cab mode in TANE SP3 I put the reverser in fwd and released the brakes. Put the throttle in T1 and it started flashing yellow as the car started to accelerate. I reset it to T0 and waited for the flashing to stop. Then back to T1. I increased the throttle to T2 then T3 then T4 as the speed increased. Probably didn't allow enough time in T3 for enough change in speed as it started flashing again in T4. So reset to T0 and repeated the sequence. I was able to run it in all 6 throttle notches with no flashing using this technique.

I did the same thing in TANE SP4 and the behavior was pretty much the same. If you need some quantitative results you can run it on the "Test Track" feature in any TANE version. I didn't. I drive steam equipment almost exclusively and they are not allowed on the Test Track. [That's an unfulfilled feature promise of the kickstarter program but I won't go into that]. But you can test this loco on the built-in Test Track in both SP3 and SP4 if you care to.

AFAIK diesel and electric locos in Trainz don't have any wheelslip. Only steam locos in CAB mode can have "actual" wheelslip where the wheels spin at a faster rate and the tractive force applied to the rail drops to 0 or a fraction of the force normally applied. For diesels and electrics there is no reduction in the tractive force applied to and resisted by the rail. AFAIK the flashing throttle for diesel-electrics and electrics is an indication of the electric drive system exceeding rated current (amp) values. I'm not sure but I think this loco is a direct diesel drive with 6 selectable gear ratios so that might not even be applicable to this type of drive.

Looking at the espec used in the VT98 06, the max tractive force is produced in notch 1 at 0.4 m/s. In this case I'd expect the loco might behave as I noted above. If this were an electric drive you might have to bump it in and out of T1 to get it moving unless there were current limiters in the drive circuits. I'm not that familiar with these types of motive power.

Bottom line results - I got flashing yellow throttle in both SP3 and SP4 which might be correct with the espec used.

Bob Pearson
 
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Hi Bob
The flashing throttle indication does indicate wheelslip in Trainz, however it doesn't indicate how much wheelslip is occurring (I'm not sure off-hand if Trainz actually supports variable wheelslip off-hand).

In regards to the wheelslip on diesel/electric locomotives, although it doesn't visually have full wheelslip effects, Trainz physics do from memory do 'proper' wheelslip calculation to some degree. Again, I'm not sure how extensive this is off-hand, but it does do some calculations here. However visually, non steam locomotives only provide a very small amount of visual wheelslip (more like wheel creep).

Regards
Zec
 
During indicated wheelslip condition, the effective tractive effort is reduced to 25% of it's maximum value. This can be changed on a per session basis using the vehicle physics rule, although I don't see any reason why you would. Within limitations of the current system 25% seems like a reasonable figure.

A few years ago when I was more active with Trainz I did extensive testing on diesel loco physics in Trainz trying to figure out how everything works, how accurate the simulation is and whether or not putting realistic values into an enginespec yielded realistic results. I concluded that for TS12 and TANE the sim could be made quite accurate. For TRS19 I am not so sure.
As you will understand if you read the rest of this post, I concentrated on diesel locos because they are waaaay simpler in enginespec terms than steamers. I figured that until I had a good grasp on accurate diesel loco (and train) physics, there was no point even attempting to wade into steam loco territory.

I have found quite acceptable results using the following parameters for US locos:

surface-area 150
moving-friction-coefficient 0.005
air-drag-coefficient 0.0026

Bear in mind that the surface area should be the frontal cross section of the locomotive. 150 is roughly correct for USA stuff. UK locos are quite a bit smaller and I use a value of 80 for them.
One of the biggest problems with getting faithful physics performance is that there are a wide number of parameters that need to be correct. Not only in the enginespec itself. For example:

In the locomotive config.txt the mass need to be correct (and in Kg) and the max-tractive-effort also needs to be correct and in newtons. I see quite a few locomotives (by some very well respected creators too) with the max tractive effort figure written in lbs. In this particular case Trainz need newtons to work correctly!

Also, none of this is any good if our rolling stock enginespecs are all wrong. Unfortunately almost all Trainz rolling stock, regardless of type, region or size, uses the same default wagon enginespec. I have settled for a "best compromise" enginespec for wagons that yields reasonable results in most situations.

In the wagon enginespec I use:

axle-count 4
surface-area 110
moving-friction-coefficient 0.005
air-drag-coefficient 0.0003

The axle count will clearly be wrong for any two axle stock, so they really should have their own enginespec.
Surface area is set at 110 which is a compromise between US and UK loading gauges.
The air-drag-coefficient is set low in order to achieve accurate results through empirical testing. Whole train air resistance is going to get very tricky very fast because the nature of a train means that wagons do not present their full frontal surface area in the direction of travel.

Of course the wagon's mass also need to be set correctly in it's config file (and in the correct units; kilograms). If the wagon is load enabled then this needs to be the empty weight of the wagon.
Finally, any products or commodities to be loaded on the wagon also need the correct value for mass in their config files. This value should be 1 for bulk commodities such as aggregates or liquids in tank cars, but not for pallets or boxes of goods and I believe should be in kilograms. Again, unfortunately, there are a gazillion different products on the DLS and very many of them have wildly incorrect mass figures which just totally throws any physics accuracy straight out of the window. Quantity before quality apparently. :(

Once you have all this data set correctly, plugging in the correct data for setting up throttle and dynamic brake curves is the last step and I have created a spreadsheet calculator that can produce these "curves" for a wide variety of locomotives from different regions and manufacturers. Again though, it is only as good as the data you feed it.

So, getting the correct train performance in Trainz depends, not only on the game's physics engine but also the information spread through numerous config files.
Unfortunately, in my experience, whilst we have many talented creators in this community few of them spend the time to get the correct values and units in all of their configs.
Having parameters spread between the enginespec itself and the loco's config.txt is very messy, further exacerbated by the mixing and matching of units of measurement everywhere. Square feet, newtons, Kilonewtons, metres per second. Some consistency would help, but for sure the biggest obstacle is the complete indifference to many content creators in setting up their configs with the correct values in the correct units!
 
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Look, there must be somebody out there on this forum who can give me a few shouts in the right direction.

Where do I look? In the engine specifications? No variable called 'wheelslip' to be found there. Do I have to tinker with 'adhesion'? Or 'moving-friction-coefficient'?

And if I'm asking a stupid question - How do I change wheelslip sensitivity to a more realistic value - then don't hesitate to tell me. Not getting any reaction is slightly frustrating, and quite unlike my pleasant experiences on this forum so far.


Glad you got some good help from the Guys.... BUT, you DID post your question, during the Thanksgiving holiday weekend..... Most of us were a bit busy stuffing our faces, watching Football, and the like. :hehe:

Man, I'm still recovering... LOL



Rico
 
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