Larry, I have studied a lot of pictures from the 50’s, and I remember the 60’s rather well.
I don’t think the two eras can be lumped together so much.
From what I have seen, in the 50’s, yes, trains were dirty, it is dirty business. And there was some degree of left over, worn out, over worked WWII rolling stock floating around. But there was masive reinvestment in rolling stock, larger better hopper cars, piggyback equipment, new bigger box cars, mechanical reefers being developed - and last ditch efforts at new, fast, shinny passenger trains. So, my studies say dirt?, yes. Decay?, not so much in the 50’s.
The 60’s and into the 70’s, now that is a different story. That was truely the beginnng of the “we don’t care”, run down, rusty, paint peeling, junk eras, not unlike today.
Sheldon