View source for 2-6-6-6

{{short description|Articulated locomotive wheel arrangement}}
[[File:Chesapeake & Ohio H-8 No. 1601 at Henry Ford Museum.png|thumb|300x300px|C&O 1601 "Allegheny Class", on display at The Henry Ford Museum in Dearborn, Michigan]]
The '''2-6-6-6''' (in [[Whyte notation]]) is an [[articulated locomotive]] type with two [[leading wheels]], two sets of six [[driving wheels]] and six [[trailing wheel|trailing wheels.]] Only two classes of the 2-6-6-6 type were built. One was the [[Chesapeake and Ohio class H-8|"Allegheny" class]], built by the [[Lima Locomotive Works]]. The name comes from the locomotive's first service with the [[Chesapeake and Ohio Railway]] beginning in 1941, where it was used to haul loaded coal trains over the [[Allegheny Mountains]]. The other was the "Blue Ridge" class for the [[Virginian Railway]]. These were some of the most powerful reciprocating [[steam locomotive]]s ever built, at {{convert|7500|hp}} (which was exceeded by only the [[Pennsylvania Railroad class Q2]] in indicated horsepower), and one of the heaviest at 386 tons for the locomotive itself plus 215 tons for the loaded [[tender (rail)|tender]].

Other equivalent classifications are:<br />
[[UIC classification]]: '''1CC3''' (also known as German classification and [[Italian classification]])<br />
[[French classification]]: '''130+033'''<br />
[[Turkish classification]]: '''34+36'''<br />
[[Swiss classification]]: '''3/4+3/6'''

The [[UIC classification]] is refined to '''(1'C)C3'''' for simple articulated locomotives.

== History ==
{{external media | width = 210px | float = right | headerimage = [[File:RR Allegheny2.jpg|210px]] 
| video1 = [https://www.youtube.com/watch?v=C7eTRkSNvOs Allegheny - Most Powerful Steam Locomotive], 1:54, Wanda Kaluza on YouTube}}
Two classes of 2-6-6-6 locomotives were built: the sixty [[Chesapeake and Ohio class H-8|H-8 "Allegheny" class locomotives]] for the [[Chesapeake and Ohio Railway]] (C&O) between 1941 and 1948,<ref>Drury (1993) pp. 83, 88</ref> and the eight AG "Blue Ridge" class locomotives for the [[Virginian Railway]] in 1945.<ref>Drury (1993) pp. 417–419</ref>  (The locomotives were Series AG on the Virginian. This was an abbreviation for "Articulated, Series G", not, as is sometimes thought, for "Allegheny".) All were built by the [[Lima Locomotive Works]]. The "Allegheny" name refers to the C&O locomotives' job of hauling [[coal]] trains over the [[Allegheny Mountains]]. C&O-1601's power output is 7,500 hp.<ref>{{Cite web|title=Chesapeake & Ohio 2-6-6-6 "Allegheny" Locomotives in the USA|url=https://www.steamlocomotive.com/locobase.php?country=USA&wheel=2-6-6-6&railroad=co#304|access-date=2021-07-09|website=www.steamlocomotive.com}}</ref>

Although it was apparent to many 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, which were among the heaviest steam locomotives ever constructed. The three-axle trailing truck supporting the firebox was unusual, carrying over {{convert|190000|lbs}}, allowing the huge firebox needed for the high power. As it turned out, steam locomotives continued in service for almost another 20 years.

Gene Huddleston's book, ''C&O Power'', reports tests of the C&O with a [[dynamometer car]] indicating momentary readings of {{convert|7,498|hp|MW|1|abbr=on}} with readings between {{convert|6,700|to|6,900|hp|MW|1|abbr=on}} at about {{convert|45|mi/h|km/h|abbr=on}}. The state of calibration of the dynamometer car is not known. The calculated starting tractive effort was only {{convert|110,200|lbf|kN|1|abbr=on}}, but no one has published a higher dynamometer horsepower for any steam locomotive.

The locomotive was built to power coal trains on the 0.57% eastward climb from [[White Sulphur Springs, West Virginia]], to [[Alleghany, Virginia]]. With one at the front and another at the back, 11,500-ton coal trains left [[Hinton, West Virginia]], and were at full throttle from White Sulphur Springs to the top of the grade at Alleghany. C&O's 2-6-6-6s also handled coal trains from West Virginia to Columbus, Ohio. Huddleston says that 23 locomotives were equipped with steam piping for heating passenger trains.

While delivering the first group of locomotives in 1941, Lima miscalculated and misrepresented the H-8s' weight. [[Maintenance (technical)|Maintenance crews]] recalculated the weight, and discovered that the H-8s weighed {{convert|771300|lb}}, which was thousands of pounds heavier than Lima first claimed. The train crews that worked with the H-8s, who were getting paid based on the locomotive's weight on the [[Driving wheel|driving wheels]] at the time, started seeing this misrepresentation as an attack on their [[livelihood]]. The C&O was forced to pay their crews thousands of dollars to make up for lost payment, and they subsequently [[Lawsuit|sued]] Lima for over 3 million dollars in 1944.<ref>{{Citation|title=The Goldem Age of steam: Trains Unlimited - When Giants Roamed: favorite fragments (original sound)| date=25 November 2019 |url=https://www.youtube.com/watch?v=1U6t-yP953s |archive-url=https://ghostarchive.org/varchive/youtube/20211213/1U6t-yP953s |archive-date=2021-12-13 |url-status=live|language=en|access-date=2021-07-09}}{{cbignore}}</ref><!-- You can find the Allegheny segment at 18:30 -->

Multiple unit operation in the diesel era removed the need to pack the highest horsepower in a single unit. The H-8's 80,000+ pound axle load demanded heavy rail and track structure.

One H-8, the 1642, suffered a crown sheet failure and subsequent boiler explosion at Hinton, West Virginia, in June 1953. The force of the explosion rocketed the boiler off the running gear towards the rear, killing all three crew.  While these locomotives had two sources of water for the boiler, a steam turbine pump-fed [[Worthington Corporation|Worthington]] hot pump and one injector, it is not known whether any were defective at the time of dispatch. According to the family of the locomotive's engineer, Wilbur H. Anderson, of Hinton, previous crews had complained of a faulty water level gauge. Anderson's widow, Georgia Anderson, was given $10,000 in compensation by the C&O.{{citation needed|date=October 2023}}

== Preservation ==
[[File:Chesapeake & Ohio H-8 No. 1604 at The B&O Railroad Museum.png|thumb|C&O 1604, B&O Railroad Museum, Baltimore, MD]]
There are only two surviving Allegheny locomotives. 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, Virginia|Roanoke]] {{circa|1969}} where it was displayed next to [[Norfolk & Western 1218|N&W 1218]]. On November 4, 1985, it was partially damaged by a flood, which washed away the ground under it and nearly turned the locomotive over. In 1987, parent company [[Norfolk Southern Railway|Norfolk Southern]] did a cosmetic overhaul on it at their [[Roanoke Shops]] before it was sent to [[Baltimore, Maryland|Baltimore]] to be displayed as the centerpiece of the then Mount Clare Junction shopping center which was adjacent to the [[B&O Railroad Museum]]. In 1989, the shopping center donated it to the museum, where it presently resides.<ref>{{Cite web |url=http://www.steamlocomotive.com/allegheny/ |title=Allegheny |access-date=2005-05-11 |archive-url=https://web.archive.org/web/20080127121645/http://www.steamlocomotive.com/allegheny/ |archive-date=2008-01-27 |url-status=dead }}</ref>

==References==

===Notes===
{{reflist}}

===Bibliography===
{{refbegin}}
*{{Drury-North American Steam}}
*{{cite book |title=Official Railway Equipment Register |orig-year= January 1953 |date=June 1996 |publisher=Railway Equipment and Publication Company, reprinted by National Model Railroad Association |volume= LXVII #3 |isbn=0-9647050-1-X}}
{{refend}}

==External links==
*https://web.archive.org/web/20080127121645/http://www.steamlocomotive.com/allegheny/

{{Whyte types}}

[[Category:Whyte notation|66,2-6-6-6]]
[[Category:Freight locomotives]]
[[Category:Lima locomotives]]