I have both the Spectrum GE Dash 8-40CW DCC and the Bachmann SD40-2 DCC, the Dash seems to be slower and not as strong on the 2.5% climb with the same amount of cars being pulled as the SD40. Is that normal?
You might have the same number of cars, but some might not be as easy rolling as others. Have you fine tuned all your cars?
Two things you need to know, first the drawbar force of the locomotive, second is the required force to pull a certain number of cars.
http://www.bachmanntrains.com/home-usa/board/index.php/topic,7063.0.html
If you are not fine tuning your locomotives and cars for uniform performance, then I would say your situation is probably normal.
Even if I swap the Locos with the other set of cars, it's the same performace. I think the Spectrum just runs in a more scale like speed. I also see two huge brass flywheel type on both ends of the Spectrum Dash 8-40CW motor which does not appear to be on the SD40-2.
It is possible that one is faster than the other. I don't have those particular locos, but maybe someone else who has will be in to comment.