Any of the single motored PW locomotives will pull better with the motor at the rear. For things like the PW GP-7, that's long hood forward. My old Phantom locomotive with a single motor in the front could barely pull it's four passenger cars on level track. With the addition of a second motor, it will pull 20+ boxcars around the club layout, including a 2% long grade. Yes, it pulls it's passenger cars, including a couple of extras just fine on the same run. This is all on Atlas track, so no magnatraction, and of course it doesn't have traction tires.
For modern stuff with two can motors, there should be minimal or no difference which way you run as far as pulling power.
