History of the locomotive:
In the early 1940s, the Chesapeake & Ohio needed new power on its Allegheny Division to move coal trains over the 80 miles of track from Hinton, WV east to Clifton Forge, VA. This run included a 13 mile .577% grade to the 2,072 foot summit of an Allegheny mountain and then a descent down a 1.14% grade to Clifton Forge. Its 2-6-6-2s were getting old and the 2-8-8-2s, delivered in the 1920s, (which used simple expansion because of tight tunnel clearances) were not up to the task.
In the 1930s, the C&O; improved the railroad by boring new tunnels and enlarging others. The Class T-1 "Texas" type 2-10-4s also arrived in the early 1930s and seems to be the choice for the Hinton to Clifton Forge run. On the brink of ordering more 2-10-4s the C&O; was approached by the Lima Locomotive Company with a new and more powerful locomotive design.
This design was a six-coupled, single-expansion articulated with 67" diameter drivers for speed, a 9' x 15' firebox with a very large boiler for steaming and 778,000 pounds of locomotive weight to assure tractive effort. The large fire box was placed behind the drivers and required a six-wheel trailing truck to support it. This gave the design a wheel arrangement of 2-6-6-6. With four 22.5" diameter x 33" stroke cylinders, a 260 psi boiler pressure and the 67" diameter drivers it could exert 110,200 pounds of tractive effort.
The C&O; placed an order for ten of these 2-6-6-6 locomotives and Lima delivered them in December, 1941. They were designated Class H-8 and assigned road numbers 1600 through 1609. With a new wheel arrangement came a new name. The C&O; selected the name "Allegheny" for the mountain range that this new locomotive would do its work.