Very nice job. A comment about the weight you added. The best balance for the loco should be between the drivers. In other words set the loco on a 1/2 inch diameter dowel or pipe crossways between the drivers. The perfect situation would be a balance but that is also almost impossible to achieve. but you can get close and get a feel for whether it is nose heavy or tail heavy.
I have a 4-4-0 that was very nose heavy when I got it. It was so bad, you could slide a piece of paper between the rear drivers and the rail. I had to take weight out of the nose and find places to put it in the cab.
A loco that is close to balanced on the drivers will pull the best it can.
