[Gehe]

Hi All,


related to the proposal to select between Advance and simple physics I would prefer to have a more detailed choice.

Some examples: I do not like the advanced adheasion model due to some effects but I would prefer that within the simple adheasion model the Curtius-Kniffler parameters can be changed.
The standard setting is related to German electrolocos of the 1930s with a transmission technique similar to the Westinghouse type. Other types of transmission or just newer locos provide significant better (higher) values.
So with the standard values in the simple model I experience wheelslip at lower tractive forces than it should be.

Another example is the drag model which is pretty advanced in the meantime. It automatically recognizes if a loco or tender is behind the leading loco and reduces the friction values for the drag accordingly.
But for many steam locos Davis values are given which cover the loco and the tender. So if one distributes these values between loco and tender by weight or by another ratio OR will reduce the tender drag values, which is wrong in this case.
A workaround here would be to increase the drag values in advance in the .eng by the factor by which they are reduced by OR in the second step.
I would prefer here to use my own values and want to be sure that there is no "post-processing" by OR. Another area is the calculation of the static or starting friction which is a very complex field. Due to the spread of values available from the different sources the ideas or opinions of the OR users may be very different here.


To avoid any misunderstanding I like OR and appreciate the development work of the OR team as well as the depth of the physics implemented very much.
Having wishes is always much more easier than specifying and coding.


Regards
Gehe

[AuzGnosis]

G'day From a pleasantly wet Auz.
Gehe's interesting resent comment;
That ran in part;<SNIP>

Gehe, on 06 January 2020 - 12:31 PM, said:

Some examples: I do not like the advanced adheasion model due to some effects but I would prefer that within the simple adheasion model the Curtius-Kniffler parameters can be changed.
The standard setting is related to German electrolocos of the 1930s with a transmission technique similar to the Westinghouse type. Other types of transmission or just newer locos provide significant better (higher) values.
So with the standard values in the simple model I experience wheelslip at lower tractive forces than it should be.

<SNIP> That bit about "German electrolocos ... transmission technique" flashed an unexpected connection for me. Early era traditional reciprocating steam locomotive were notorious for their uneven delivery power over each cylinder cycle directly transferred to the wheels. I have not looked at, or for anything in OR (or elsewhere) about tractive forces, wheelslip &/or transmission technique. To-date I have been quite happy to assume Peter with his helpers behind the Great Zig Zag Railroad simulation have devoted more than sufficient consideration to the issue. But the serendipitous flash I just had is that little prudent reading up on adheasion models would give me a better understanding of pros & cons of high speed geared steamed locomotives such built by the German & French before WW2 & diesel power eclipsed such dreams. Could anybody here point me to books(in English) or webpages on this subject.

Many thanks, W'Shawn Gray