That is cool how many cars?
I think this train was in the 50 car range. The longest I've run on this layout has been 75 cars, but that was on the outside track without any significant grades. It is the Paradise and Pacific Railroad club at the Scottsdale McCormick-Stillman Railroad Park. It is an awesome club with great people and a fun layout to operate and work on. It is 32'x40' and has four mainlines to operate on. The club record is around 140 cars, but they were all ore cars.
Typically, the outside two tracks are on automatic control as the layout building is a public facility and we want trains always running when there are visitors. However, they can be switched to user operation as well. Here is old video of the outside track with another freight train being pulled by my Williams PAs. I think a lot of the same cars are in this one too.