Billy - Without a doubt the GGD B&O passenger cars are the gold standard! Unfortunately for me GGD cars are out of my budget range. In addition the GGD cars would not be able to negotiate the curves of my layout.
I grew up on the B&O's Washington Division between Baltimore and DC. As a youth I saw many of the B&O's premier passenger trains and locals come whizzing by my favorite chosen train watching spot. I used to climb a signal tower just so I could see into the strata dome car .. most likely the Capitol Limited.
Since these two B&O Premier trains passed through Connelsville ... You may be interested in reading this book by Joe Welsh " Baltimore & Ohio's Capitol Limited and National Limited" published by Voyageur Press. It documents these two train's histories complete with photos of cars and locomotives used throughout the train's history.
Another book of interest would be "The Royal Blue Line" by B&O historian Herbert Harwood .. published by Greenberg. Also " The Baltimore and Ohio Railroad" by Reynold and Oroszi published by Voyageur Press.
To Jonathan's point, I always found the B&O passenger trains to be made up of interesting equipment ... mostly a mix heavy weight cars that were reconditioned and given a streamlined appearance by Mt. Clare Shops in Baltimore. Occasionally there would be a light weight stream lined car or two in the consist. B&O didn't purchase many streamlined passenger cars directly from manufactures. Instead they chose to refurbish and upgrade existing heavy weight cars to give a streamlined appearance.
A B&O passenger train of particular beauty was the Cincinnatian designed by Olive Dennis, a design engineer employed by the B&O. She did a terrific job designing the interior and exterior of this train. P7 Pacifics purchased by the B&O in 1927 were given a streamlined shroud which gave the locomotive a sleek Art Deco look. The 5 car train was inaugurated in December of 1946 running between Baltimore and Cincinnati and vice versa during daylight hours.
Good luck in assembling your B&O fleet of passenger equipment.
Here are some photos of part of my B&O fleet.
18 inch coach by K line.
18 inch Station Sounds Diner " Martha Washington" by Lionel. Although this car was assigned to the Columbian which ran to St. Louis it may have occasionally been assigned to B&O passenger trains passing through Connellsville? BTW -B&O's Columbian was the first air conditioned passenger train in the U.S.
As Johnathan mentioned regarding the B60b RPO by Weaver; here is my Weaver B&O RPO car. Note: I believe this livery to be after1960. I think ( and I could be wrong here ) this livery was adapted after the 1963 B&O and C&O merger. I just thought I'd show it anyway even though the livery may go beyond your historic window of time. Livery aside, this type of RPO car would have definitely seen service during the period you inquired about.