Railworks America

RSC Empire Builder Lightweigth Coach shows 25 (tons, metric, imperial, long, short?) meanwhile, Heavyweights from Golden Age of Railroading show 40 (whatevers) - neither of these are close to the tonnage I see on-line for such Pullman Cars, not even close.

I started looking because 15 RSC Lightweight cars behind 2 of the Berkshires from here could not make it up the 1.8% Marias Pass, but 1 Berk with 11 Heavyweight coaches was FLYING with steam to spare... (I'm also wondering if the 2nd Berk was helping or was just a rolling anchor)

Don't know the Unit of Mass in TS2017. The docs should provide that information.
A good rule of thumb for the weight of US passenger cars is: 1 US ton (2,000 lbs) per 1 foot of length for 'heavyweight' cars and between .60 and .65 US ton per 1 foot of length of 'lightweight' cars.

Wouldn't the units of mass, etc. depend upon the country in which each route is located?

The unit of mass is Metric Tonnes. The blueprints use metric for most measurements regardless of what country you are in. And to make it even simpler, the Metric Tonne and Imperial ( or Long ) Ton are nearly the same weight, 2204 pounds vs 2240 pounds so there is little error in mixing them up. The US Ton or Short Ton is 2000 pounds. I am sure there is some interesting history explaining why their ton ( and their gallon for some reason ) are short.

Wayne