The B&O used to run a pair of trains called the Trailer Jets. Where did these trains run and when were this discontinued? I know they lasted until the mid-80's.
I believe that these two trains were remnants of the Western Maryland. In WM days they were called Alpha Jets due to their heritage on the Alphabet Route. They were high priority merchandise that were operated in conjunction with N&W between Ohio and Port Covington.
As a sidenote, there are still Western Maryland trains operated by CSX. The grain trains that Wheeling and Lake Erie run over CSX from Connellsville to Hagerstown via the Lurgan Sub are the result of concessions that Chessie/CSX made in order to win approval for the abandonment of WM From Big Pool to Connellsville.