[plainsman]

Has anything changed in the way OR uses gross power to account for transmission efficiency? In older versions, I know there was a loss of about 2% to account for loss in the traction motors, but that would still not account for all transmission loss. Translation loss of gross power at the rail, would be a total of about 6% in the best AC designs, to as much as 20% in some old first generation diesels. I am still adjusting my power value for transmission efficiency. If something has changed, then we need a specifiable parameter for transmission efficiency, as no general value will account for all types. If the program still uses gross power less about 2%, then it would be easy enough to adjust the gross power to power at the rail in the .eng file power parameter. I just need to know how it is currently implemented?

[R H Steele]

Knowing it was probably not very accurate I have been differentiating between Tractive HP and Gross HP, on the average adding about 100HP to the tractive HP

Quote

Comment ( Performance Ratings == Gross HP 4500 == Traction HP 4400

taken from the Dash9 OR standard engine file.
I did this because in the OR diesel engine block there is a line that specifically notes "MaximalPower" ... a peculiar word to use. It may have some technical meaning that I am not aware of.
For Maximal Power I use the Gross HP, the tractive HP is used to compute the ORTSMaxTractive Curves.
I know this does not answer your question ( it will probably take a developer with knowledge of that section of code ), but it's what I'm doing in practice until I know for sure how OR handles this. Interesting question.
While not on point .... I've also wondered if OR takes into account the gear ratio? Is there a default for all diesels...seems unlikely.