The 2-6-6-6 is an articulated locomotive with two leading wheels. Only two classes were built: the "Allegheny" class by Lima Locomotive Works and the "Blue Ridge" class for the Virginian Railway.Rivarossi has reproduced 3 versions of these Chesapeake & Ohio 2-6-6 articulated steam locomotives in H0 scale: HR2950, ˜Allegheny No 1601, HR2951, ˜Allegheny No 1632 and HR2952, ˜Allegheny No 1653.Sixty "Allegheny" class locomotives were built for the Chesapeake and Ohio Railway between 1941 and 1948, primarily to haul coal over the Allegheny Mountains. With a power output of 7,500 hp, they were among the heaviest steam locomotives ever built. The tenders had a 25,000-gallon water tank and a 25-ton coal bunker, with the rear section higher to fit turntable limits, leading to weight distribution issues.Only two Allegheny locomotives survive today. One, C&O 1601, was donated to The Henry Ford Museum in 1956, where it remains on display. The other, after being damaged by a flood in 1985 and cosmetically restored, is now housed at the B&O Railroad Museum.