SP 0-6-0, on 27 February 2018 - 12:30 PM, said:
ORTS physics are a mess and need overhauling. I will second that.
Thanks for your constructive, helpful and encouraging comment.
Jean-Paul, on 26 February 2018 - 03:16 PM, said:
Overall, how an engine having a closed cutoff (neutral position) could slip ???? :rolleyes:
I don't know... But I think it's really a bug !!!
The OR model probably did not contemplate that somebody would open the throttle wide up, with the reverser in the 0 position.
I will have a look, and "fix" this sometime next week.
Jean-Paul, on 26 February 2018 - 03:54 PM, said:
Must also say that permanent sanding, even before trying to start, seems not to have any effect on these parameters : slip factor remains, without or with, @ 0.20...
It is not realistic to apply sanding before commencing to move. If this did happen, it would create little piles of sand on the tracks, and add to the starting issues.
Jean-Paul, on 27 February 2018 - 09:52 AM, said:
I did a run with only 350 hauled metric tons, and was also unable to start on the same 1.05 % step, whilst when same train runs on flat ground, steam engine could develop efforts widely larger than those resulting from adhesion calculations.!.
There are a number of factors, including the starting resistance of the train, and the steepness of the slope, adhesive weight of the locomotive, driving technique, etc, that could make it difficult or impossible to start a train, especially on a wet slope.
The tractive effort, and the rotational forces are different values. For example, the tractive effort is an "average" value of the force available to move the train. The rotational force of a steam locomotive will vary as the wheel rotates, and it will reach a maximum value at certain points around the cycle. This maximum value can be in excess of the tractive effort, hence why it might seem that the locomotive is slipping before its tractive effort is reached. Diesels are different, and have constant rotational forces around the full cycle.
Do you have load tables for the locomotive in question?
After I have adjusted the code next week, I would be happy to participate in some additional testing if it is of interest. If so, it would be necessary to set an agreed scenario, and test set.
Thanks
EDIT: Just out of interest, it appears that this locomotive had a Factor of Adhesion = 3.88. Locomotives with FoAs less then 4 were more prone to wheel slip.