If you do mean MODEL DIE CASTING (MDC)/ROUNDHOUSE, 60' HARRIMAN STYLE CARS, this is what you could have or need.
1) OBSERVATION CAR, UP YELLOW AND BROWN PAINT, MDC #480-6164
2) RAILWAY POST OFFICE CAR, MDC #480-6124
3) BAGGAGE CAR, MDC #480-6134
4) COMBINATION CAR, MDC #480-6144
5) DINNER CAR, MDC #480-6154
6) COACH CAR, MDC #480-6174
I count SIX cars in the MDC/ROUNDHOUSE set. Not counting the 50' HARRIMAN style EXPRESS REEFER, MDC #480-6114.
Now just in case, RIVAROSSI made STREAMLINE CARS that have round roof's but come in 72' length.
Oh how I wish a body could upload an image from their own files and not have to use a photo hosting site.
Oh, and hi BillR78.
As far as I know, Rivarossi never made any Harriman cars. The ones you have are probably Model Die Casting / Roundhouse cars from before the line was bought by Athearn. MDC did make an observation car matching the other cars.
Rivarossi did make 60' heavyweight cars with clerestory roofs (not rounded like Harriman cars), they were also sold under Walthers and Hornby names.
Did Rivarossi ever make a 60 foot Harriman style observation car?
I have the other 4 cars in the set lettered for UP and would like to add this car.
Thanks