I have a nice Hogwart's Express that I upgraded to command and fan driven smoke, etc. The only issue is, I got some extra cars to pull, and it had real problems pulling seven or eight cars, five is about it's limit if you throw in a 2% grade. Given the weight of the locomotive, it's clear that the issue is the wimpy set motor that Lionel equips them with. I sent a second engine off to Frank Timko to see about a motor upgrade, it just arrived back. This was a stock conventional Hogwart's Express locomotive, I wanted to see the motor installation and see if it ran properly before I committed to doing all the work to go to command. I'm happy to report that it seems to run great, and it certainly has a lot more pulling power, the object of the exercise!
Interesting solution to the width of the motor, I never thought about grinding a little of it off!