Very nice. Any amount of weight added in the right place helps. Just a warning it is possible to add too much. I added so much weight to a brass 2-10-0 that the drive coupling tube was slipping on the motor. I revamped to a universal shaft and all was good until it started clicking while pulling around 70 cars. The idler gear in the gear box broke. I then removed some weight and it's been a great performer since.
Pete.