Central Railroad of New Jersey RDC-1 #551 is listed for sale at the Ozark Mountain Railcar web site:
http://www.ozarkmountainrailcar.com/detail.asp?id=489&n=Central-Railroad-of-New-Jersey-RDC-1-551-REDUCED
Some of the details from the listing:
"Built by the Budd Company in 1954 for the Central
Railroad of New Jersey, eventually sold to New Jersey Transit who then retired
the car and sold it into private ownership. Interesting car in that most of the
mechanical equipment including the two engines are still on the car."