Around how many freight cars can a GP7 realistically pull?

[jim currie]

Hi everyone. I'm glad to be back.

I'd like to know how many freight cars can a single GP7 realistically pull?

Also, do you have advice for me who's having trouble with the tender of a Bachmann 4-8-4 from the Overland Limited derailing on a turnout?

depends on the grade on the GP7 , check the wheels on the tender with a NMRA gage.
jim