I purchased castings for the front truck from "Little Engines".  The hearts swing without binding after hours of filing. The axles, wheels and journals were made out of stock.  A few months after I finished it, I decided to extent the distance between the wheel centers from 9" to 11" as per the GS-4.  The picture below is with 9" centers.

  Here's it is below stretched to 11" centers.

The next step was to work on the rear trucks.  Again, the castings were bought from "Little Engines".  The wheels, axles and journals were made from stock.