The "1945-48" listing is probably best. The sans-serif (Futura / Fleet of Modernism) lettering is not a service indicator - it was supposed to be the new look for all cars. Someone in management took a dislike to it and pulled the plug, so not a lot of equipment other than the Pullmans and other streamlined passenger cars (which also got the maroon window band and elaborate striping) kept it for any length of time.