Here's a Rivarossi Pullman, converted into a solarium/observation. While it has air conditioning, battery boxes, and a water system, most of the brake gear is visible in this photo...
...and a look under a wooden baggage/express car...
Other than a small toolbox and the two large tanks (Pintsch Gas, for lighting the car), most of the rest you see is the UC Type brake system, common to many passenger cars. It consists of the universal valve, a brake cylinder, and three air reservoirs - service, auxiliary, and emergency. Naturally, there's lots of piping some other smaller hardware, too.
Wayne
Another source of passenger underbody info is Brasstrains.com. They frequently will show an excellent shot from underneath. Of course, later cars will have better detailing.
Here, for example, is an underbody shot of a W&R SP&S #46, a 30' RPO baggage:
Ed
There were some good drawings of passenger car underbodies, mostly Pullmans, in a number of issues of Mainline Modeler. While the drawings included various types of air conditioning, electrical supply, and water systems, it also showed brake equipment. I'd offer some photos, but photobucket's site seems to be down at the moment. I'll add another post here when they get their act together.
Bowser (Cal-Scale) makes a brake set for cars like this (PN 190-300). Here's the instruction sheet that comes with it:
It is, of course, generic. If you want to get closer to exactly arranging the parts to recreate a particular prototype, then photos will help you figure out the variation you are interested in.
A possible source of photos for this purpose and also for paint and lettering info would be Paul Faulk's "Seaboard Air Line Color Guild to Freight and Passenger Equipment".
looking for some direction on where i can find information on the brake details of a 60' RPO car. I am working on an old wooden RPO car model (Walthers) from the 1970s (HO scale) that i want to decal for the Seaboard Airline railroad. Any help would be appreciated.
Thanks.