PRR D2

PRR D2 & D2a

Class B A #138 (later class D2a)
Type and origin
Power type Steam
Builder PRR Altoona Works
Build date 1868–1872 (D2);
1881–1882 (D2a)
Total produced 20 (D2); 45 (D2a)
Specifications
Configuration 4-4-0
UIC classification 2′B
Gauge 4 ft 8 1⁄2 in (1,435 mm)
Leading wheel
diameter		 28 in (711 mm) (D2)[1]
30 in (762 mm) (D2a)[2]
Driver diameter 62 in (1,575 mm) (D2)[1]
68 in (1,727 mm) (D2a)[2]
Wheelbase 22 ft 5 5⁄8 in (6.85 m)[2][3]
Length 54 ft 5.44 in (16.60 m)[2][3]
Width 9 ft 0.94 in (2.77 m)[2][3]
Height 14 ft 8 in (4.47 m) (D2)[3]
14 ft 11 in (4.55 m) (D2a)[2]
Weight on drivers 52,500 lb (23.8 tonnes) (D2)[3]
53,750 lb (24.4 tonnes) (D2a)[2]
Locomotive weight 80,500 lb (36.5 tonnes) (D2)[3]
82,200 lb (37.3 tonnes) (D2a)[2]
Tender weight 51,400 lb (23.3 tonnes) (D2 & D2a)[2][3]
Locomotive and tender
combined weight		 131,900 lb (59.8 tonnes) (D2)[3]
133,600 lb (60.6 tonnes)[2]
Tender type Eight-wheel with water scoop
Fuel type Soft coal
Fuel capacity 8,000 lb (3.6 tonnes)[3]
Water capacity 2,400 US gal (9,100 l; 2,000 imp gal)[3]

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 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 B2a in the post-1895 scheme; forty-five of them were constructed.[4][5]

References

  1. ↑ 1.0 1.1 1.2 Dredge, James (1879). The Pennsylvania Railroad. London: Engineering magazine.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Pennsylvania Railroad. "Class D2 diagram". PRR.Railfan.net. Retrieved 2008-08-19.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Pennsylvania Railroad. "Class D2a diagram". PRR.Railfan.net. Retrieved 2008-08-19.
  4. ↑ 4.0 4.1 "PRR Steam Roster". Northeast Rails. Retrieved 2007-12-31.
  5. ↑ Warner, Paul T. (1924). Motive Power Development on the Pennsylvania Railroad System. Philadelphia: Baldwin Locomotive Works.
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