I don't get it. This may be yet another MSTS gotcha, but I am having difficulty using the A&M T6's (A&M_T6_14) front coupler and the Gon_96022_E gondola. No matter how slow I couple to the car, it lurches forward and the activity ends with a derailment (even with derailments disabled in options).

Perusing the respective .eng and .wag file shows they both have (nearly) the "latest" physics (break values are larger) so I don't get why it doesn't work. Anybody have any ideas or have you been able to get it to work? Or am I just SOL and must avoid using the front coupler at all costs?

What activity is this happening in? What siding/etc?

My use of the front coupler on the T-6 was very stable, hence using it in activities with front coupler use.

Andre

Many times this is the result of bounding box problems. Check the bounding boxes visually first. I don't know why this happens on some systems and not others. Perhaps it is where you are coupling. Can you use the front coupler with other cars? Try coupling to this car on a straight section, and make sure your coupling speed is 2 mph or less. If none of this works, I will be glad to help you figure this out by looking at the file values for you.

Hi Andre,

The particular activity was Eureka Springs Switcher 1, however I can reproduce the problem quite easily in explore mode.

The coupler fails at Eureka Springs on the wye at ArTieCo 2. It appears to work just fine on a straight (or maybe its the grade rather than the turn that's causing the problem; ArTieCo 2 is on a rather steep grade).

To demonstrate the problem, I created a consist of the T6 and the gondola, started in explore mode at Eureka Springs (heading west), successfully switched the gondola from behind the engine to the front then backed up to ArTieCo 2 dragging the gondola via the engine's front coupler. Then with engine brake on, uncoupled the gondola, notch 1 in reverse, very slowly released the engine brakes which caused the engine to roll forward ever so slightly (despite being at notch 1 in reverse; there is quite a grade there) and attempt to recouple with the gondola. The gondola bounces forward and results in a derail.

I am inclined to think this is an insolvable problem; yet another MSTS gotcha.

Joe, only if you are interested and think you can shed some light on it I'd appreciate any help you feel up to providing. The front coupler problems are plentiful enough to drive anybody nuts and I certainly don't want to throw fuel on the fire.

I had a problem in The Berryville Switcher activity with a similar derailment involving a gondola.Of course,RS1 #22 is the engine on that job,but the gondola was one of the loaded Railgons from Yaffe's.Attempting to front couple to my 3 car string caused a derailment every time,no matter what speed.And the funny thing is that I was just thinking to myself how smooth the front coupler is on #22.I'm thinking the gondolas may have an issue?

Guys,

Look at the .s file with shape file viewer, press CTRL-B to see the display in shape file viewer, and write down the length shown there.

Then, post that and the first 10 lines of the .wag file, along with the .sd file, and I will look at it. I don't have A&O yet or the rolling stock. I suspect that it is the bounding box on the gondola.

Joe,

Here you go:

w: 3.049
h: 2.315
l: 15.494

SIMISA@@@@@@@@@@JINX0t1t______
Shape ( Gon_96022_E.s
ESD_Detail_Level ( 0 )
ESD_Alternative_Texture ( 0 )
ESD_Bounding_Box ( -1.524151 0.020145 -7.125 1.524529 2.335105 7.125 )
)

SIMISA@@@@@@@@@@JINX0D0t______

Wagon ( Gon_96022_E
Type ( Freight )
WagonShape ( Gon_96022_E.s )
Name ( "AM Gon1 MT" )
Size ( 3.00341m 4.53307m 15.05m )
Mass ( "27.396t" )
WheelRadius ( 33in/2 )
InertiaTensor ( Box (3.00341m 4.53307m 15.05m) )
...

If it helps, SFV shows the red bounding box completely enclosing the couplers.
Thanks for the help.

Have you try with others Gondola , is the same cars but i just check the SD files and the bouding box is
different ?????

SIMISA@@@@@@@@@@JINX0t1t______
Shape ( Gon_69015_R.s
ESD_Detail_Level ( 0 )
ESD_Alternative_Texture ( 0 )
ESD_Bounding_Box ( -1.524151 0.020145 -7.047292 1.524529 2.335105 7.047292 )
)


Gaetan

15.494 - 0.3 = 15.194 - 0.6 = 14.594 / 2 = 7.297

2.315

3.049 / 2 = 1.5245

I take the SFV length, subtract .3 for coupler end thickness, subtract .6 to get to BB and IT lengths, divide by 2 to get each BB parameter.

I set the height to the actual height, except for the BB height. In the case of low cars like flats and gondolas, I always make the BB at least 3.1. I discovered this because I would have problems with unloaded flats, but the BB height of loaded flats included their "loads" and was always higher and usually gave no problems.

I divide the width by two to get the BB numbers.

Inertia tensor and BB are set essentially the same.

Change the lines to what is in the bold text and try that.


ESD_Bounding_Box ( -1.524151 0.020145 -7.125 1.524529 2.335105 7.125 )

ESD_Bounding_Box ( -1.5245 0.9 -7.297 1.5245 3.1 7.297 )


Size ( 3.00341m 4.53307m 15.05m )

Size ( 3.049m 2.315m 15.194m )

InertiaTensor ( Box (3.00341m 4.53307m 15.05m) )

InertiaTensor ( Box (3.049m 2.315m 14.594m) )

What'd he just say?

Kerry

Gaetan,

Yes, the problem is present with all 4 gondolas. In addition, I tried it with us2hoppercar and the same thing happens. The problem is present on a curve in the track but not on a straight. I doubt the grade has anything to do with it.

Joe,

I put your changes into all 4 gondola .sd and .wag files and it didn't help. BTW: Where does MSTS get its pointer to the .sd file? Is there an entry in the .s file making the .s and .sd point to one another? Is there something else I must do to ensure MSTS sees updated .sd files?

I won't have time to mess with this further for the next few days, so if you suggest something else for me to try, you might not hear my feedback for a bit. Thanks for the input so far.

I believe that the problem lies in the bounding box length values in the .sd files of the T6 locos. as shipped, the values are:

ESD_Bounding_Box ( -1.485648 0.717961 -6.573025 1.485648 4.338297 6.573025 )

using logic similar to that which Joe stated above, I changed the line to read:

ESD_Bounding_Box ( -1.485648 0.717961 -6.473025 1.485648 4.338297 6.473025 )

I ran a few tests last night on curves and all went well...

Tim B

I used the wye to run around the train.Now I would be coupling to the tanker from the additive track.Same derailment.Now I'm thinking it's coupling on the curve that's the problem.

Coupling on curves is a problem. It can be "helped" sometimes with coupler settings. Next to try is looking at coupler section in these cars. Please post them here and I will give a "suggestion".

In this situation I can just avoid the curve.As I said before the front couplers on these units work quite smoothly,so I don't mind the occasional workaround to deal with MSTS' quirks.This is the best route available at this time.