Postcard depiction of the Vista Dome car of the Chessie.
Chesapeake and Ohio Railway
The card was issued by Chesapeake and Ohio between 1944 and 1950.  Their plans for The Chessie began in 1944.  The train wasn't built until 1948, due to WWII.  By 1950, the line's passenger service had fallen off to the point where they needed to either use the cars for other trains or sell them to other railroads.  Postmark is hard to read.  Going by the return address for Augusta, GA, with a zone number and not a Zip Code, this was mailed before 1965.
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