I tested the following:
and Trainorama C32.
I ran the HUB set with each locomotive from my lower staging yard across the full main line to my upper staging yard.
All locomotives hauled the HUB set with ease up my 1 in 40 grades some of which are on 30" (760mm) curves.
I took a video of each climb up the last long 1 in 40 bank which has a curve right at the top end which can usually bring a locomotive to it's knees if it is overloaded.
The trains were run on DCC at speed steps ranging in the 40 - 50s of 128 possible steps so perhaps at around half power equivalent for DC (if you can really say that with DCC). Basically they were ran at a slow to medium speed to ensure that they weren't using momentum gained on the flat sections of the layout to coast up the grades.
Here is the video, you can see that each locomotive is not having any problems with hauling the HUB set. I believe that each locomotive would have handled the 7 car HUB set as well.