My Stainzes would never pull that many BEFORE I retrofitted them with MTH Fan Driven smoke units! Especially since my rolling stock had metal wheels and if passenger cars and lighted, the extra drag from the current pickups rubbing the wheels also played a factor.-, as did any sound car with a large speaker in it. I built a helper car out of an old AristoCraft Gondola and their newest motor block they used in the Little Critter and the Egg Liner series of loco's, then with that and the Stainz I could pull around 25-35 cars on my small layout. Used the helper mid-train and included the SFX railsounds by Phoenix in it as well.