WOW!!! Teach me to ask a simple question 
This has turned into a fascinating discussion.
First, I want to thank everyone who has offered info on my question - once again, I always seem to learn something new on the Forum. Second, I assure you, I have always had the rule - My road, My rules!!! The last train I ran was a Vision Line Big boy pulling a string of intermodal cars, so historic accuracy isn’t one of my major concerns. That being said, earlier this year, I started putting together my version of a 1950’s era NYC Hudson Line commuter train, and, for once, I wanted it to be pretty accurate. Although my version sports an electric engine, it’s consist is two coaches and a combo, so the placement of the combo at the end seemed oddly interesting. As has been noted, having combo/baggage cars on commuter trains was not unheard of - I have seen pics of some trains on the Old Put in the early diesel era that had them... so I guess I will mix up my consist every now and then. One of those pics showed the combo directly behind the engine and the caption referred to it as a mail train, so based on Bob’s info on Postal Regs, I can also run my own mail train!!!
Thanks again to all for the education.
