Trying to fix the GN F7 Empire Builder's friction

[generalwo]

I am having a go at modifying the GN F7 Empire Builder to get rid of the bugs it has. I will upload the fixes to this website once they're done. I'm only a beginner at modifying rolling stock, but have some experience as a software developer so I'm familiar with messing with XML files and the like.

There are two bugs in this train that I am trying to fix: The B key not toggling the bell properly (so you need to hold down the button) and the excessive friction which is causing the train to slow down even when coasting downhill. Hopefully, once I've figured the solution, I can also use that to fix the DB BR420, which has a similar problem.

I'm RW_Tools to edit the train's .bin files.

So far, I've managed to fix the bell problem by changing the inputmapper by editing Assets\RSC\EmpireBuilderPack01\InputMappers\F7_Expert.bin and changing the "name" attribute from IncreaseControlStart to ToggleControl.

Now onto the friction. I have determined the problem is caused by the coaches only. If I use a different engine but the same coaches, the problem persists, but if I swap out the coaches with different ones, and keep using the original F7, the problem goes away.

I have been comparing the weight and friction values of the coaches with other coaches that don't appear to have this problem, to see if I can spot the cause of the problems. Oddly, it doesn't seem friction-related at all. For example, this is the 60SeatDayNite coach:

Code: Select all

   
   <Mass d:type="sFloat32" d:alt_encoding="0000000000003940" d:precision="string">25</Mass>
   
...

   <DragCoefficient d:type="sFloat32" d:alt_encoding="000000C0CCCC1C40" d:precision="string">7.2</DragCoefficient>
   <RollingFrictionCoefficient d:type="sFloat32" d:alt_encoding="000000C07493583F" d:precision="string">0.0015</RollingFrictionCoefficient>
   <DryFriction d:type="sFloat32" d:alt_encoding="000000000000E03F" d:precision="string">0.5</DryFriction>
   <WetFriction d:type="sFloat32" d:alt_encoding="000000000000D03F" d:precision="string">0.25</WetFriction>
   <SnowFriction d:type="sFloat32" d:alt_encoding="000000403333C33F" d:precision="string">0.15</SnowFriction>
   <SandFrictionMultiplier d:type="sFloat32" d:alt_encoding="000000C0CCCCF43F" d:precision="string">1.3</SandFrictionMultiplier>

These values are the same for all the different types of coaches in the pack. Looking at one of the Pacific Surfliner coaches, which are not affected by the friction issues, I've found that the friction values are in fact identical to the Empire Builder coaches. Even the "d:alt_encoding" values are identical. Only the Mass variable is different at 57.

It seems that, unless I've missed something, the actual friction attributes are not the cause of the problem. But then where else can the problem lie? My questions are as follows:

Did I miss something?
Do you have an idea where else the problem may lie, so that I can give that a look?
Is there any documentation available that may give me a bit more insight into what I'm doing?

[Chacal]

For documentation, we have the dev docs here in the file library.

[dimovski]

Apparently, the friction coefficient is correct, I've calculated 0.001559.

The drag coefficient is significant aswell... and without going through all the maths, I'd guesstimate it at 3.36.

[generalwo]

Thank you for your replies.

Dimovski, that's pretty interesting. It doesn't seem like the train slowing down is friction-related at all, I'm beginning to suspect it has to do with the brakes not fully releasing.

Chacal, I have looked through the files on this site, but not found anything about train physics. Did I miss it?

[Chacal]

It's called "developer docs". It was, and mostly remains, the only documentation for Railworks blueprints, even if it's outdated.
It downloads as an executable that installs a set of pdf documents. One of them documents the engine blueprint, and there's a section about physics. Same for the wagon blueprint.

For tracking down issues such as brakes not fully releasing, I suggest you have a look at the "Traisim helper" utility by Havner.
viewtopic.php?f=56&t=12392

Possibly you can use this to display variables not represented in the F5 HUD.

[generalwo]

Thanks! I've found the files.

I'll give that Trainsim Helper tool a go too. It looks pretty nifty in general, and not just for fixing the friction bug.

[generalwo]

Well, it's been a while but I've decided to throw myself at this problem again, and I've made a little progress this time. I'm posting this update for those who are interested or are dealing with the same issue.

It seems that the coaches aren't causing the problem, but the locomotive! The coaches need 110 psi before they fully release the brake, and the locomotive can only provide 90 psi.

Swap the locomotive out with one that uses 110 psi, such as the F59PHI that comes with the Pacific Surfliner route, and the coaches behave normally, no excessive friction

So what I need to figure out is how to mod the F7 locomotives to operate at 110 psi instead of 90, and this problem should be solved. Once I do, I'll upload the fix to the file library, along with a fix for the bell switch.

Edit 30 dec 2015: I've released the fix, it's in the file library: http://railworksamerica.com/index.php/d ... ccessories

[Derek]

Email DTG and have them look into it.

We are looking into older packs to address out standing issues.

[BNSFdude]

Its not like the issue went unaddressed by the Beta team at the time.

[Derek]

happy days.
;)

As I said email DTG and we will look into it.

thanks
d