Eddie,
Then you'll have to go to York or some local train shows to pick up some usable New Haven cars and repaint them to match! A Royal Blue passenger set was sold pre-war with stamped metal cars. But no plastic passenger cars were painted to match the loco post war. See? I always like to think of projects for other guys! Hey, I have enough of my own. I found a bunch of shells to make scale length cars last Spring at York, so they're out there. They're going to be painted New Haven colors.... eventually. 
