I usually weight all of my rolling stock heavier than NMRA standards also. I run trains that are between 35 and 50 cars and don't have any trouble with 1 or 2 locomotives pulling any of my trains, going up the hill, I need 3 SD40-2's or 2 SD90's, I don't think it will wear out the locomotives any sooner, but it does keep things on the track. I only have a derailment when someone runs a switch.