Mel may not have had one, but here's mine I did last year from a Westerfield kit as NWP #1957. Since I model 1939 had to leave off the cool NWP herald and roadname (shown here from Andrew's site). Depending on your year I would def go with NWP.
Speaking of USRA DS, since model 1939, I have built a bunch, including both F&C and Westerfield. I have just embarked on a serous effort to build an additional 6 more using Ertl models. I'm not sure of the heritage of the tooling for these, but sure looks Gould'ish (Tichy)? The trucks are wrong, but easy swap to Tichy Andrews. All of the paint schemes and lettering are laughable. They serve as a good place to start as details are good with basic underframe brake details and separately applied grabs. Add some additional brake detail, uncoupling levers of your prototype (rotary or Carmer), a weight inside, and then paint & decals.
Will post all six for next week's "Workbench Thursday".