Pennsylvania Railroad D5
Builder's photo of D5 #930
Type and origin Power type Steam Builder PRR Altoona shops Build date 1870–1873 Total produced 18
Specifications Configuration: ​  • Whyte 4-4-0  • UIC 2′B Gauge 4 ft 8+1⁄2 in (1,435 mm) Leading dia. 26 in (660 mm)[1] Driver dia. 56 in (1,422 mm)[1] Wheelbase 19 ft 9.6 in (6.04 m) (locomotive); 40 ft 6.1 in (12.35 m) (with tender)[1] Length 49 ft 6.2 in (15.09 m) (locomotive and tender)[1] Width 8 ft 10+1⁄2 in (2.71 m) (cab roof)[1] Height 14 ft 8 in (4.47 m) (rail to top of stack)[1] Adhesive weight 40,800 lb (18.5 tonnes)[1] Loco weight 65,200 lb (29.6 tonnes)[1] Tender weight 40,800 lb (18.5 tonnes)[1] Total weight 106,000 lb (48.1 tonnes)[1] Fuel capacity 6,500 lb (2.9 tonnes)[1] Water cap. 1,600 US gal (6,100 L; 1,300 imp gal)[1]

The Pennsylvania Railroad's steam locomotive class D5 (formerly Class G, pre-1895) comprised eighteen lightweight 4-4-0 locomotives for light duty, maintenance-of-way and branch-line service, constructed at the railroad's own Altoona Works (now owned by Norfolk Southern) during 1870–1873.^[2]

They shared many parts with other standard classes, although less so with the heavy 4-4-0s on account of their lighter build; instead, they shared some components with 0-6-0 switcher classes F and H (later B1 and B2).^[3] The Class G locomotives had a straight-topped boiler, unlike the wagon-top of the other 4-4-0 classes.