Nice job, Gary, particularly for an early effort. If I may, let me offer a suggestion, or two, for you to consider during future weathering sessions on this sort of car.
The ends of your car look very good, however less so in side view. The car's lettering is far too "fresh" looking, as is the overall body paint, in spite of the rust patches. I would suggest that next time you start out by giving the entire car a thin application (a "wash") of something like Floquil, or Polyscale, Weathered Black. This will tone down/fade the lettering, as well as give the car's appearance a more aged and service-worn look.
Then, after completing your other weathering steps, consider applying a thinned application of Earth, or Dust, to about the lower 1/3 of the car to represent road dust kicked up onto the car during its travels. Finally, make the rust color on your couplers a much darker rusty hue.
NYW&B