Wow Ralph. It's a good thing that you got it out on the road for a spin. I really like the faded paint and the rust effects of the cab roof, trucks and stack. Is there a proto photo for this one just to follow your approach to weathering?
Added another 424 to my roster.If interest you can follow the build on the reading modeler web site. Here's the unit mated with 5202. Here she is as the 2nd unit leading a coal train.634 is a geep 7 unit.