Ed,
One of the nicest trucks in our local club, a '40s model "L" Mack City Service Ladder truck, is in complete, total original condition. And, it is
GREEN. Called "The Green Goddess", which also happens to be the nick name of some '50s era National Fire Service trucks in England, which became famous for serving front-line duty during a huge strike of the fire service there. The Green Goddesses became legend.
I had a friend who used to say "any truck that isn't red, never got close enough to a fire to get ripe!".
I don't agree, I think there's room for all colors.
Except slime green. THAT was an AWFUL idea . . .

By-the-way,
HERE is a photo of my beloved Rosie just after the engine came out.
-Michael