4-8-4

From Free net encyclopedia

Revision as of 21:43, 15 March 2006; view current revision
←Older revision | Newer revision→

Image:NW 611.jpg Under the Whyte notation for the classification of steam locomotives, a 4-8-4 locomotive has four leading wheels arranged in a leading truck, eight coupled driving wheels and four trailing wheels in a trailing truck.

The equivalent UIC classification is 2'D2'.

The 4-8-4 was an obvious progression from the 4-8-2 "Mountain" and the 4-6-4 "Hudson" types, combining the 4-8-2's ability to have more weight on the driving wheels (leading to greater traction, and allowing a larger, more powerful locomotive) and the 4-6-4's larger firebox supported by a 4-wheel trailing truck, allowing for freer steaming, particularly at speed.

The first 4-8-4 was produced in 1927 by Alco for the Northern Pacific Railway, and the type was therefore named "Northern". Southern railroads in particular obviously didn't find this name very suitable, so they chose other names for their 4-8-4 classes.

Railroad Name
Canadian National Railway Confederation
Central of Georgia Railroad Big Apple
Chesapeake and Ohio Railway Greenbrier
Delaware, Lackawanna and Western Railroad Pocono
Denver and Rio Grande Western Railroad Western
Grand Trunk Western Railroad Confederation
Lehigh Valley Railroad Wyoming
Nashville, Chattanooga and St. Louis Railway Dixie
Ferrocarriles Nacionales de Mexico Niágara
New York Central Railroad Niagara
Richmond, Fredericksburg and Potomac Railroad General, Governor, Statesman (three different classes)
Southern Pacific Railroad Golden State (or General Service)
Western Maryland Railway Potomac

The Northern type proved to be the best choice of locomotive arrangement for both express passenger and fast freight service. It wasn't suited to heavy drag freight, but faster and lighter trains were well suited to the type.

Given that the 4-8-4 was a late development and Northerns were often the 'name' passenger power at the time of steam's demise, many were saved from the scrapper's torch and are now preserved in museums, or in the case of a lucky few, kept in running condition.

The Union Pacific Railroad has a Northern on its roster that has never been retired from service, UP 844, the last steam locomotive built for the UP. It is used for charter service and for publicity for the railroad. It also holds the unique distinction of being the only steam locomotive never retired by a Class I railroad.

Preservation

Many 4-8-4 locomotives have been preserved in museums, and a few are kept in operational condition. Some of the more notable of this type are: Image:ATSF 3751 19920000 IL Streator.jpg

Template:Whyte types