- The cars in this era don't show a lot of heavy areas of rust like modern cars do.
- There is a fairly consistent coating of dirt/soot on the dirty cars.
- There is a range of "dirty." The density of the coating of soot likely has to do with how many months/years a car has gone without a repaint.
- The roofs tend to be darker.
- Some of the roofs show paint failure.
- Some of the wood roofs and running boards show repairs.
- A few cars (very few) show "chalking" or streaking of the lettering, like the X29 in the third photo.
- Reefers tend to be cleaner. I know that PFE washed their cars, presumably others did as well.