Rob, Not sure if this will help, but I did do a skim of the "Write Up Books" from the 1930s for South Tacoma for boxcar service, or accident repairs. The table below shows the car serviced, year, and that it was "Car Painted Complete". Given that these cars were built in the mid 1920s, indicates that for at lease some cars, repaints were happening relatively soon. But that might have only been due to accidents, not regular maintenance.
