2-6-6-6 "Allegheny" Locomotives in the USA

An Allegheny Locomotive

What was the most powerful steam locomotives ever built? The Big Boy? Nope. What was the heaviest steam locomotive ever built? The Big Boy? Well, maybe, maybe not. Read on to find out the answer.

In the 1930s, the C&O improved its railroad by boring new tunnels and enlarging others. The Class T-1 "Texas" type 2-10-4s also arrived in the early 1930s and seemed to be the choice for hauling its 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. 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 agreed and 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. An article by King in "Trains" in the early 2000s stated that the C&O Alleghenies cost around $270,000.00 each.

The tenders for these new locomotives were of the largest type used on the C&O, with a 25,000 gallon water tank and a 25 ton coal bunker. In order to keep the overall length of the locomotive and tender within the limit that existing turntables could handle it was necessary to make the rear section of the tender higher, thus causing more weight to be at the rear than the front. The tender had a six-wheel leading truck, but an eight-wheel trailing truck was needed to carry the weight in the rear.

In operation, one "Allegheny" leading and one pushing could move a 140 car loaded coal train up the mountain from the Hinton terminal. At the top the pusher would be taken off, turned around and sent back to the Hinton terminal. The single leading "Allegheny" could handle the decent down the mountain to Clifton Forge where it would be turned around for a return trip with a train of empty coal cars.

The C&O had 23 of its "Alleghenies" equipped with steam heat and signal lines for passenger service, but they were used sparingly, pulling an occasional heavy mail train or a troop train during World War II. The "Allegheny" may have been the ultimate freight locomotive. They were able to achieve a very impressive record even though they were used in a manner that didn't fit perfectly with their design. The Allegheny boilers were capable of delivering up to 8000 HP! This was far greater than any other reciprocating steam locomotive could develop. However, the C&O used the H-8s in "coal drag" service where they were unable to realize their full potential as high speed locomotives. The C&O Alleghenies were designed to haul 5,000 tons at 45mph, but unfortunately were used to haul trains of 10,000 or more tons at 15mph. C&O's 2-6-6-6s were very impressive locomotives. However, they were never used to their full potential. The "Allegheny" was truly magnificent in its role, but as good as it was it could not win the battle with the diesel. The C&O's "Alleghenies" were taken out of service beginning in 1952 with the last fire dropped in 1956.

It should also be noted that the Alleghenies were some of the most powerful steam locomotives ever built. At 40 MPH they could generate 7,500 HP. This power was only exceeded by the PRR Q-2 Class (7,987HP). By contrast the UP Big Boy could generate a maximum of 6,200 drawbar HP.

Fortunately, two of the C&O "Allegheny" type locomotives survive today, number 1601 at the Henry Ford Museum in Dearborn, MI and number 1604 at the B&O Railroad Museum in Baltimore, MD.

Upon retirement, 1604 was sent to the scrap lines behind the diesel shops at Russell, KY. It was donated to the Roanoke Transportation Museum circa 1969. At Roanoke, 1604 was displayed next to N&W 1218. On November 4th, 1985, it was partially damaged in a flood (N&W 1218 was gone by this time). During that flood, it almost turned over when the ground was washed out from under it! Fortunately, it leaning up against an overhead bridge pier which prevented it from falling any further. The NS did a cosmetic overhaul on 1604 at the Roanoke Shops before for it was sent (around 1987) to Baltimore to be displayed as the centerpiece of the Mt. Clare Junction shopping center which was adjacent to the B&O Museum. The shopping center was literally built around 1604. In 1989, the failing shopping center decided that 1604 was too big and decided to donate her to the B&O Museum. 1604 was moved from the mall onto B&O Museum property in early 1990 by SW-1 Pere Marquette 11. During the early 1990s, there was a rumor going around that the CSXT was considering starting their own steam excursion program. They reportedly sent some mechanics to check the condition of 1604 to see if it was feasible to restore it to operating condition! Apparently, those plans never came to fruition. Today, the cab has been cosmetically restored and lighting has been placed in the firebox so that it can be viewed.

Numbers 1600, 1602, 1603 and 1605-1659 scrapped between 1952 and 1956.

The Virginian was the only other railroad to have bought the 2-6-6-6. They needed more power during World War II and ordered eight 2-6-6-6s. They took delivery of them from the Lima Locomotive Works between March and June of 1945. These locomotives were designated as Class AG and assigned road numbers 900 through 907. On the Virginian these copies of the C&O "Alleghenies" were called "Blue Ridge" type locomotives. They used them for hauling coal trains well into the 1950s. All of the "Blue Ridge" locomotives were retired by 1955 and were scrapped by 1960.

Allegheny and Blue Ridge Locomotives

Number of "Allegheny" Type Locomotives Built by Year
Road Numbers1600-16091610-16191620-1644900-9071645-1659
C&O1010 25 1560
VGN 8 8

Railroads that used 2-6-6-6 "Allegheny" Locomotives in the USA (data provided by Steve Llanso of Sweat House Media)

Surviving Examples of 2-6-6-6 "Allegheny" Locomotives in the USA

No.ClassF.M. WhyteGaugeRailroad LineLocationStatusBuilder InfoNotes
1604H-82-6-6-64'-8½"C&O B&O Railroad Museum, Baltimore, MDdisplayLima #7824, 1941From Russell, KY the Roanoke, VA
1601H-82-6-6-64'-8½"C&O Henry Ford Museum, Dearborn, MIdisplayLima #7821, 1941