I wish it would pull more. Mine pulled 15 cars up a 1.5% grade around an 18" radius. When I converted it to DCC I lost some of the weight in the boiler and some of the pulling power.
I added wt to the cab and I also added lead to the front porch under the smoke box cover. It regained all it had lost and then some.
The locomotive is smooth and quiet. I have ordered two more. I love them. For my home layout 15 to 18 cars is a normal train, and this locomotive can do that, so for my purpose it is fine.
If you are looking for something that will pull 40 cars, this isn't for you.
I have a secret weapon for pulling power though
A lifelike GP 20 split frame with flywheels sitting in an express reefer, ensure this Mountain will pull 40 cars when I want it to!!!!!