Class D6 (formerly Class K, pre-1895) on the

Pennsylvania Railroad The Pennsylvania Railroad ( reporting mark PRR), legal name as the Pennsylvania Railroad Company, also known as the "Pennsy," was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. At its ...

was a class of

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, Fuel oil, oil or, rarely, Wood fuel, wood) to heat ...

. Nineteen were built by the PRR's Altoona Works (now owned by

Norfolk Southern The Norfolk Southern Railway is a Class I freight railroad operating in the Eastern United States. Headquartered in Atlanta, the company was formed in 1982 with the merger of the Norfolk and Western Railway and Southern Railway. The comp ...

) between 1881 and 1883. They were equipped with drivers. Seven were later converted to 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 from the previous maximum of about . The innovation was not wholly new, having been first seen on the

Philadelphia and Reading Railroad The Reading Company ( ) was a Philadelphia-headquartered railroad that provided passenger and freight transport in eastern Pennsylvania and neighboring states from 1924 until its acquisition by Conrail in 1976. Commonly called the Reading Railro ...

'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 The Baldwin Locomotive Works (BLW) was an American manufacturer of railway locomotives from 1825 to 1951. Originally located in Philadelphia, Pennsylvania, it moved to nearby Eddystone, Pennsylvania, Eddystone in the early 20th century. The com ...

in 1881 for six locomotives constructed for the

Central Railroad of New Jersey Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

; these were followed by the

locomotives, which garnered more attention for this design feature, in addition to having larger drivers than most previous 4-4-0s.

References

{{DEFAULTSORT:Pennsylvania Railroad class D06 4-4-0 locomotives 2′B n2 locomotives D06 Railway locomotives introduced in 1881 Scrapped locomotives Standard-gauge locomotives of the United States Steam locomotives of the United States