Pennsylvania Railroad class D3

The Pennsylvania Railroad's steam locomotive class D3 (formerly Class C, pre-1895) comprised sixty-seven 4-4-0 locomotives intended for general passenger and freight service, constructed at the railroad's own Altoona Works (now owned by Norfolk Southern) during 1869–1881.^[2] They were the third standardized class of locomotives on the railroad and the most numerous of the early standard types; they shared many parts with other standard classes.^[3]

PRR D3
PRR D3 #274 in its builders' portrait.
Type and origin Power type Steam Builder PRR Altoona Works Build date 1869–1881 Total produced 67
Specifications Configuration: ​  • Whyte 4-4-0  • UIC 2′B Gauge 4 ft 8+1⁄2 in (1,435 mm) Leading dia. 28 in (711 mm) (D2a)[1] Driver dia. 62 in (1,575 mm)[1] Wheelbase 22 ft 5+5⁄8 in (6.85 m)[1] Length 54 ft 5.44 in (16.60 m)[1] Width 9 ft 0.94 in (2.77 m)[1] Height 14 ft 8 in (4.47 m)[1] Adhesive weight 50,950 lb (23.1 tonnes)[1] Loco weight 79,100 lb (35.9 tonnes)[1] Tender weight 51,400 lb (23.3 tonnes)[1] Total weight 130,500 lb (59.2 tonnes)[1] Tender type Eight-wheel with water scoop Fuel type Soft coal Fuel capacity 8,000 lb (3.6 tonnes)[1] Water cap. 2,400 US gal (9,100 L; 2,000 imp gal)[1]

This design differed from the Class A (later D1) mainly in its smaller drivers for greater tractive effort for freight haulage. Like all the early standardized 4-4-0s on the PRR, the Class C had a wagon-top boiler with steam dome and a firebox between the two driving axles.^[2][4]