[midneguy]

Hi guys :)

I've noticed a somewhat strange behavior between my Frisco 1500 engines and their tenders, and thought I would ask in case anyone could explain what I'm seeing... When moving back and forth in the engine, I notice that the tender often times appears to either push or pull the locomotive. As an example, if the engine is sitting at rest with the brakes released, setting the reverser forward and opening the throttle will cause the tender to lurch forward against the engine - before the engine itself even starts to try to move. After moving for a bit, the tender will "settle" into what is the correct distance I want it to be from the engine. Bringing the engine to a stop, the tender initially stays where I want it to be but it then drifts backward again and out of position. Do any of you have any ideas why the tender would seem to be acting as though it's attempting to move on it's own?

And related to that, what I really want is to eliminate the movement of the tender relative to the engine at all times - instead of looking like a worn out engine with a worn out drawbar... I've attempted to tune the coupling entries to eliminate the apparent slack action, or spring action, but without success... Can anyone recommend the correct coupling parameters to use to eliminate this unwanted movement between the engine and tender? The engine is set up with an automatic coupler on the front and bar on the rear, while the tender has a bar coupling on the front and automatic on the rear. For reference the coupling entries of both the engine and tender are provided below:

Engine:


Coupling (
Type ( Bar )
Spring (
Stiffness ( 5000000n/m 1200000n/m )
Damping ( 3800000n/m/s 1300000n/m/s )
Break ( 54000kn 54000kn )
r0 ( 0cm 5cm )
)
CouplingHasRigidConnection ( 0 )
Velocity ( 0.2m/s )
)
Coupling (
Type ( Automatic )
Spring (
Stiffness ( 1200000n/m 5000000n/m )
Damping ( 1300000n/m/s 3800000n/m/s )
Break ( 54000kn 54000kn )
r0 ( 2cm 5cm )
)
CouplingHasRigidConnection ( 0 )
Velocity ( -0.2m/s )
)

Tender:


Coupling (
Type ( Automatic )
Spring (
Stiffness ( 1200000n/m 5600000n/m )
Damping ( 1300000n/m/s 3800000n/m/s )
Break ( 54000kn 54000kn )
r0 ( 2cm 5cm )
)
CouplingHasRigidConnection ( 0 )
Velocity ( 0.2m/s )
)
Coupling (
Type ( Bar )
Spring (
Stiffness ( 5000000n/m 1200000n/m )
Damping ( 3800000n/m/s 1300000n/m/s )
Break ( 54000kn 54000kn )
r0 ( 2cm 5cm )
)
CouplingHasRigidConnection ( 0 )
Velocity ( -0.2m/s )
)

[copperpen]

Far as I can work out you have to set the r0 for the bar coupler to 0cm 0cm. This however results in the tender being very close coupled, but using any other figure gives the result you have observed. For OR it should be possible to add a physical bar coupling model to maintain a proper gap between engine and tender, might even work for MSTS as that sim accepts a FRED at the rear with no errors. You then have, engine+coupler+tender.

[atsf37l]

Derek, I'm glad to hear someone else is experiencing this. Since I loaded 2422 I have noticed a lot of slack action between engines and tenders. That is one place where slack should not occur. One would think it should be simple to exclude movement in connections between the type "Engine" and "Tender," eh?

Copperpen, what you suggest might be a help with the zero-length "CrewCars" we have had to use to put crews in cabs of some of our engines that have used up the FreightAnim to split the engine to get it into MSTS. Ultimate solution, of course, is to put those parts back together for an OR version of the engine and then either make the crew part of the shape or load it with an FA, but that requires the builders to put other projects on hold while they retrofit previous engines. Most I have talked to are willing to do so but it will take a while and in the interim our cabs will be Ghost Locos, empty of humans, and in some cases the highly visible controls (throttle quadrants, gauges, etc.) that are attached to them. Perhaps that engine+coupler+tender concept might work with the CrewCars. Something to look into Derek? :bigboss:

[copperpen]

Just an addition to my previous, I removed the rigid statement as well. This causes problems in MSTS ( trains jumping tracks ) and might also do the same in ORTS, but have to wait and see on that one.

[jared2982]

If 0ing out the r values in the coupler statement fixed the movement between engine and tender then could the coupling distances then be adjusted to gain the proper gap? Of course this is probable a case where two seperate .wag files are needed.

[midneguy]

Hey guys :shock6:

OK... backing up to the original matter at hand... Copperpen - I tried your coupling value recommendations and eliminating the rigid connection lines totally and was delighted to see that I had the results I wanted :bigboss: I tried the engines and tenders on the Feather River Route and the tenders stayed exactly where I wanted them to be without bouncing around or showing any slack behavior, so I thought I had achieved victory.

And then... well... I tried testing the engines on another route, in this case the 3DTS Donner Pass route. Imagine my surprise when I noticed the slack action between the engines and tenders was still there like it had been yesterday. Note that this was using exactly the same .eng and .wag files between the two routes, but definitely producing different coupling behavior.

What would explain the behavior of coupling parameters being different between two different routes when exactly the same .eng and .wag files are being used? I'm definitely puzzled now... http://www.elvastower.com/forums/public/style_emoticons/default/book2.gif

I haven't had a chance to try to test different crew cars and how they may behave, or as we've seen now misbehave in OR... I know some of those were pretty dicey to get set up even in MSTS, causing reversed camera angles in some cases and being difficult to keep the crews from shaking around. I wonder if those crew cars which were touchy to begin with might be the reason OR doesn't like them? In my case with the 1500's I've been testing, I was fortunate that following Copperpen's coupling recommendations ended up with the tender exactly where I wanted it to be behind the engine distance wise - at least on the Feather River Route. It probably depends on the particular models though if one can simple adjust the coupling distances to zero and adjust the size to match.... On some models it may still require the main pivot point to be shifted to make everything really line up perfectly. I'm not positive about the crew cars but my first thought is that it might still be necessary to rebuild the crew car shape and its bogie positions, etc, and possibly the corresponding engines and tenders they're intended to be used with to get the coupling distances to still work out right?