On Jun 7, 2012, at 3:11 PM, Brian Rochon wrote:

I notice that all of the listed colors show a start date of 1944. Did
these railroads all change their color formulas in that year or would
they be accurate for earlier years? I model 1943, so that means
freight cars last painted as far back as the late 1930's?

Brian,
Based on the ACF paint samples from 1931 to 1952, there was a general
trend from darker, browner, and flatter paints during the 1930s to the
early 1940s to freight car colors that were lighter, with more red, and
more glossy in the immediate postwar years and into the 1950s. There
were some exceptions to this rule with UP being one example that used
an oxide color in the late 1930s.

Several ACF Santa Fe "Mineral Brown" paint samples for cars built
during the 1930s to 1944 were quite dark brown and flat. Comparing to
Tru-Color Paint #19, they are a perfect match. By the late 1940s ATSF
Mineral Brown had changed considerably with more of a red-brown hue.

Around the end of World War II the paint manufacturers
apparently reformulated paints and the names often used "synthetic" in
the description.
Regards,
Ed Hawkins