[darwins]

Now if a 2-cylinder engine makes a 1/4 slip, then will a 3-cylinder engine make a 1/3 slip?

[Laci1959]

darwins, on 07 April 2022 - 11:50 AM, said:

Now if a 2-cylinder engine makes a 1/4 slip, then will a 3-cylinder engine make a 1/3 slip?

The video is a bit misleading. Usually such four cylindrical machines are compaund locomotives. At start-up, the four cylinders get fresh steam, and when it starts moving, they switch to a compound drive.
Of course, everything else in America may start directly with 2 cylinders in 4 places. Maybe it's easier to move?

[cesarbl]

I'm doing some changes in OpenRails adhesion model, and inserted that changes into steam locomotives. This is the result:
https://youtu.be/6W2lVWpI7OE
Adhesion is a very complex topic, and the parameters have to be adjusted carefully to obtain the desired results. The critical parameters are inertia, coefficient of adhesion and the slope of the slip characteristics.

[scottb613]

cesarbl, on 08 April 2022 - 04:40 AM, said:

I'm doing some changes in OpenRails adhesion model, and inserted that changes into steam locomotives. This is the result:
https://youtu.be/6W2lVWpI7OE
Adhesion is a very complex topic, and the parameters have to be adjusted carefully to obtain the desired results. The critical parameters are inertia, coefficient of adhesion and the slope of the slip characteristics.

Hi Cesar,

That looks like a big improvement over what we have now - with the warp speed wheel slip.

I can imagine this is something that is extremely difficult to model - given all the variables at play.

I haven't had a chance to test Peter's changes yet.

Regards,
Scott

[rickloader]

darwins, on 07 April 2022 - 11:50 AM, said:

Now if a 2-cylinder engine makes a 1/4 slip, then will a 3-cylinder engine make a 1/3 slip?

Not so much : rather the 3 cylinders get stuck on dead centres so there is no forward movement. I remember seeing these Bulleid pacifics having to be started in reverse then the driver frantically winds the reversing loco into forward gear. When steam is re- applied the whole train is jerked forwards with a terrible crash. Lets not simulate this though!
But anecdotes aside: thanks to all for this very welcome development
Rick

[Laci1959]

cesarbl, on 08 April 2022 - 04:40 AM, said:

I'm doing some changes in OpenRails adhesion model, and inserted that changes into steam locomotives. This is the result:
https://youtu.be/6W2lVWpI7OE
Adhesion is a very complex topic, and the parameters have to be adjusted carefully to obtain the desired results. The critical parameters are inertia, coefficient of adhesion and the slope of the slip characteristics.

Hello.

This is a very nice job. Congratulations.
Sometimes it is very difficult to set the parameters.

https://kephost.net/p/2022/14/2239_bec8ea8274c8.png

Hello.

This is a very nice job. Congratulations.
Sometimes it is very difficult to set the parameters.

The illustration shows the starting traction force (80 ... 85 kN) and the coefficient of adhesion (210 ... 260 N / kN). There is no way I can reconcile this with the Curtius Kniffler parameter.
Inertia is already a case in the other thread.
Unfortunately, all my manuals used to train drivers contain this information.

Sincerely, Laci 1959

[ATSF3751]

Very well done cesarbl! I sure wish we could implement this into open rails eventually.

Brandon

[Jonatan]

cesarbl, on 08 April 2022 - 04:40 AM, said:

https://youtu.be/6W2lVWpI7OE

Excellent work on that, it looks very good indeed. Lets implement it immediately. :good: