The Allegheny steam locomotives where massive articulated engines built by Lima locomotive works with the bizarre wheel arrarrangement of 2-6-6-6; their name comes from the locomotive's first service with the Chesapeake and Ohio Railway beginning in 1941. The other was the "Blue Ridge" class for the Virginian Railway. These were one of the most powerful reciprocating steam locomotives ever built at 7,500 HP, and one of the heaviest at 386 tons for the locomotive itself plus 215 tons for the loaded tender. Two classes of 2-6-6-6 locomotives were built; the sixty H-8 "Allegheny" class locomotives for the Chesapeake and Ohio Railway (C&O) between 1941 and 1948, and the eight AG "Blue Ridge" class locomotives for the Virginian Railway in 1945. Though it was apparent to knowledgeable people in the railroad industry that reciprocating piston driven steam locomotives might soon be replaced by diesel power, Lima and C&O set out to build the ultimate in high power steam locomotives and they succeeded. No diesel engine ever surpassed the output of these giants. There are only two surviving Alleghenies. Upon retirement in 1956, 1601 was donated to The Henry Ford museum in Dearborn, Michigan where it has been on display indoors since. 1604 was initially sent to C&O's scrap lines behind their diesel shops at Russell, Kentucky. It was then donated to the Virginia Museum of Transportation in Roanoke circa 1969.

Thank you @thenastynurse13 for the idea of writing about the Allegheny locomotives!