Just read this blog post:
http://swrails.com/2014/03/19/he-aint-m ... hes-heavy/
I don't have much free time these days so I won't be trying this out myself, but the way I see it, to make an UP SD70AH all one would need to is increase the tonnage and the traction effort at rail (slightly) in the simulation BP.
other references:
https://akronrrclub.wordpress.com/2014/ ... this-year/
http://www.trainorders.com/discussion/r ... ?1,3300107

