Emerging from the (coal) mist! This rarely visible unit until recently served as a plant switcher for the Mirant Energy coal-fired power plant in Alexandria, VA. Usually hidden behind rows of coal hoppers, it now maintains a silent vigil as the power plant has been shut down and remaining coal stocks taken away. The prime real estate adjacent to the Potomac River is to be redeveloped; the fate of the few other shippers on the industrial track unknown but presumably also to disappear.
Since a Mirant logo is (barely) visible on the side of the cab, I have chosen to report it with reporting marks known to belong to Mirant Energy (MTIX) and the road number 9614 visible on the side of the headlight assembly. this unit was built in 1957 as B&O 9614, the first of 8 SW1200 switchers ordered. It later wore Chessie colors and was sold in May 1984 according to the B&O roster on trainweb.com. Its ownership since is not known to me. Now visible through some bushes from a public trail.
Big time thanks to RP participant Charles Freericks who uncovered this gem while recently visiting in town. Always humbling when an out-of-towner knows more about the area. :)
John Fuller's comment reminds me that I forgot to cite his excellent article on the industrial track serving this location: John Fuller, "The Uncertain Future of Norfolk Southern's Historic PEPCO Lead," Railpace, May 2012, pp. 21-25.