PRR D6
Encyclopedia
Class D6 on the Pennsylvania Railroad
was a class of 4-4-0
steam locomotive
.
Nineteen were built by the PRR's Altoona Works between 1881–1883. They were equipped with 78 inches (1,981 mm) drivers.
Seven were later converted to 72 inches (1,829 mm) drivers and classified D6a.
The D6 was one of the first American 4-4-0s to place the firebox above, rather than between, the locomotive's frames
.
This added about 8 inches to the possible width of the firebox, enabling a larger, easier to fire and more powerful locomotive; the maximum fire grate area increased to about 35 sq ft (3.25 m²) from the previous maximum of about 18 sq ft (1.67 m²).
The innovation was not wholly new, having been first seen on the Philadelphia and Reading Railroad's 1859 Vera Cruz, designed by James Milholland
of that road and built in their own shops; the Reading used this design until the invention of the Wootten firebox
in 1877.
It was subsequently adopted by the Baldwin Locomotive Works
in 1881 for six locomotives constructed for the Central of New Jersey; these were followed by the Pennsylvania Railroad locomotives, which garnered more attention for this design feature, in addition to having larger drivers than most previous 4-4-0s.
Pennsylvania Railroad
The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....
was a class of 4-4-0
4-4-0
Under the Whyte notation for the classification of steam locomotives, 4-4-0 represents the wheel arrangement of four leading wheels on two axles , four powered and coupled driving wheels on two axles, and no trailing wheels...
steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
.
Nineteen were built by the PRR's Altoona Works between 1881–1883. They were equipped with 78 inches (1,981 mm) drivers.
Seven were later converted to 72 inches (1,829 mm) drivers and classified D6a.
The D6 was one of the first American 4-4-0s to place the firebox above, rather than between, the locomotive's frames
Locomotive frame
A locomotive frame is the structure that forms the backbone of the railway locomotive, giving it strength and supporting the superstructure elements such as a cab, boiler or bodywork. The vast majority of locomotives have had a frame structure of some kind...
.
This added about 8 inches to the possible width of the firebox, enabling a larger, easier to fire and more powerful locomotive; the maximum fire grate area increased to about 35 sq ft (3.25 m²) from the previous maximum of about 18 sq ft (1.67 m²).
The innovation was not wholly new, having been first seen on the Philadelphia and Reading Railroad's 1859 Vera Cruz, designed by James Milholland
James Milholland
James Milholland was acting President of the Pennsylvania State University, serving from the death of Ralph Dorn Hetzel in 1947 until 1950.-References:*...
of that road and built in their own shops; the Reading used this design until the invention of the Wootten firebox
Wootten firebox
The Wootten firebox is a type of firebox used on steam locomotives. The firebox was very wide to allow combustion of anthracite coal waste, known as Culm. Its size necessitated unusual placement of the crew, examples being camelback locomotives...
in 1877.
It was subsequently adopted by the Baldwin Locomotive Works
Baldwin Locomotive Works
The Baldwin Locomotive Works was an American builder of railroad locomotives. It was located in Philadelphia, Pennsylvania, originally, and later in nearby Eddystone, Pennsylvania. Although the company was very successful as a producer of steam locomotives, its transition to the production of...
in 1881 for six locomotives constructed for the Central of New Jersey; these were followed by the Pennsylvania Railroad locomotives, which garnered more attention for this design feature, in addition to having larger drivers than most previous 4-4-0s.