Pennsylvania Railroad class D2
| PRR D2 & D2a | |||||||||||||||||||||||||||||||||||||||
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| Class B A #138 (later class D2a) | |||||||||||||||||||||||||||||||||||||||
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The Pennsylvania Railroad's steam locomotive class D2 (formerly Class B, pre-1895) comprised twenty 4-4-0 locomotives intended for mountain passenger helper service, constructed at the railroad's own Altoona Works (now owned by Norfolk Southern) during 1869–1880.[4] They were the second standardized class of locomotives on the railroad and shared many parts with other standard classes.[1]
This design differed from the Class A (later D1) mainly in its smaller drivers for greater tractive effort in mountainous terrain. Like all the early standardized 4-4-0s on the PRR, the Class B had a wagon-top boiler with steam dome and a firebox between the two driving axles.
In 1881, the PRR took the Class B design and modified it to produce more locomotives for express passenger service, with 68-inch (1,727 mm) drivers like the earlier Class A. These new locomotives were designated Class B A, and were classified as D2a in the post-1895 scheme; forty-five of them were constructed.[4] [5]
References
[edit ]- ^ a b c Dredge, James (1879). The Pennsylvania Railroad. London: Engineering magazine.
- ^ a b c d e f g h i j Pennsylvania Railroad. "Class D2 diagram". PRR.Railfan.net. Retrieved 2008年08月19日.
- ^ a b c d e f g h i j Pennsylvania Railroad. "Class D2a diagram". PRR.Railfan.net. Retrieved 2008年08月19日.
- ^ a b "PRR Steam Roster". Northeast Rails. Retrieved 2007年12月31日.
- ^ Warner, Paul T. (1924). Motive Power Development on the Pennsylvania Railroad System. Philadelphia: Baldwin Locomotive Works.
