[hroch]

Hello,

When the locomotive is in a wheelslip, the coefficient of adhesion does not decrease. In 0:00:25 and 0:00:58 min on video.
https://www.youtube....h?v=NCm6hvCQXQ8
In 0:01:22 min randomly drops conditions from 100% to 80% and then it goes back. This happens randomly all the time.
After time 0:1:36 when the locomotive is running idle/throttle=0, axle out of force and comp axle of force oscillate. They should be zero.

When the diesel locomotive is running idle/throttle=0, axle out of force and comp axle of force oscillate too. When stopping they also oscillate. They should be zero.
https://youtu.be/HlD5vJbOB1g

When the steam locomotive is running idle/throttle=0, axle drive force, axle out of force and comp axle of force oscillate. They should be zero.
https://youtu.be/W2NA0Zo867Y

Please repair.

[cesarbl]

Quote

When the locomotive is in a wheelslip, the coefficient of adhesion does not decrease. In 0:00:25 and 0:00:58 min on video.
https://www.youtube....h?v=NCm6hvCQXQ8

Only the static CoA is displayed, and it is expected to stay constant. You can see that the CoA changes because less tractive force is being produced.

Quote

In 0:01:22 min randomly drops conditions from 100% to 80% and then it goes back. This happens randomly all the time.

This is intentional. As I see in the code, it represents a "random slippery spot". Maybe we can disable it if adhesion random change is set to zero.

Quote

After time 0:1:36 when the locomotive is running idle/throttle=0, axle out of force and comp axle of force oscillate. They should be zero.

This is a limitation of the model. There are oscillations but they are very small, and they won't produce any side effect. I don't think they can be fixed.

Also note that axle out force should not be zero if the throttle is closed. Wheels carry some rotational inertia that goes against train deceleration, so some force is indeed applied to the rails even with no tractive force.

Quote

When the steam locomotive is running idle/throttle=0, axle drive force, axle out of force and comp axle of force oscillate. They should be zero.

For steam locomotives there's another bug IIRC, that produces tractive force if the regulator is closed. This has to be fixed.

[steamer_ctn]

hroch, on 12 July 2023 - 02:33 AM, said:

When the steam locomotive is running idle/throttle=0, axle drive force, axle out of force and comp axle of force oscillate. They should be zero.

As Cesar has suggested there will be some residual force even when the throttle is at zero due to the inertia of the wheels and rods on the wheel.

Unlike the diesel the steam locomotive does not have a uniform inertia throughout the full wheel revolution. In part of the wheel revolution the force would be positive as the rods are rotating downwards (adding weight (force) to wheels) and negative when the rods are rotating upwards (subtracting weight (force) to wheels).

[cesarbl]

The bug I mentioned is this: http://www.elvastowe...post__p__295914

Was this fixed?

[steamer_ctn]

cesarbl, on 12 July 2023 - 11:40 PM, said:

The bug I mentioned is this: http://www.elvastowe...post__p__295914

Was this fixed?

I was looking at tweaking it as part of some changes that I am working on.

[hroch]

cesarbl, on 12 July 2023 - 03:19 AM, said:

Only the static CoA is displayed, and it is expected to stay constant. You can see that the CoA changes because less tractive force is being produced.

In my video the force will drop from 215kN to 80kN The speed of the wheel is 250kmh. 80kN in wheelslip is too much. The locomotive is still accelerating.
Watch this video https://www.youtube....h?v=1jKBN31anMg at 1:44:08. The locomotive starts moving and then a wheelslip occurs. The locomotive does not accelerate in a wheelslip. The speed on the speedometer is around 120 km/h.

cesarbl, on 12 July 2023 - 03:19 AM, said:

This is intentional. As I see in the code, it represents a "random slippery spot". Maybe we can disable it if adhesion random change is set to zero.

My adhesion settings


I would be happy the "random slippery spot" to be disable when the random adhesion change is set to zero.

[cesarbl]

Quote

In my video the force will drop from 215kN to 80kN The speed of the wheel is 250kmh. 80kN in wheelslip is too much.

Do you have any reliable source for this statement? It contradicts existing literature. For example, "Creep forces in simulations of traction vehicles running
on adhesion limit" by Polach (2005), suggests that adhesion at slip is a 40% of the total static coefficient.

If you can provide some papers which state otherwise, I'll investigate the issue.

[joe_star]

steamer_ctn, on 12 July 2023 - 09:15 PM, said:

As Cesar has suggested there will be some residual force even when the throttle is at zero due to the inertia of the wheels and rods on the wheel.

Unlike the diesel the steam locomotive does not have a uniform inertia throughout the full wheel revolution. In part of the wheel revolution the force would be positive as the rods are rotating downwards (adding weight (force) to wheels) and negative when the rods are rotating upwards (subtracting weight (force) to wheels).

Hello

I have noted that the inertia seems to have a net positive tendency at higher speeds (higher than the rated critical speed of the locomotive). When viewing the axle force being applied in the Extended F5 GUI, at lower speeds indeed a positive Green force is counterbalanced by a negative "Red" force intermittently during each revolution of the wheel, but at higher speeds the negative force dissapears leaving only a positive force being applied and resulting in the locomotive actually accelerating on a level grade with the regulator off

I have noticed this with several "MSTS" configured steam locomotives to date.

Here are 2 screenshots:-

Low speed - we can see a push & pull inertial reaction

https://i.ibb.co/6rLy63t/Open-Rails-2023-07-29-04-42-56.png

At high speed - there is only a positive push inertial force and the locomotive is accelerating!

https://i.ibb.co/fM91nw8/Open-Rails-2023-07-29-04-39-29.png