Pennsylvania Railroad class R1

PRR R1
R1 #4800 in its builders' portrait
Type and origin Power type Electric Builder Baldwin-Westinghouse Serial number BLW: 61817 Build date 1934 Total produced 1
Specifications Configuration: ​  • Whyte 4-8-4  • AAR 2-D-2  • UIC 2'D2' Gauge 4 ft 8+1⁄2 in (1,435 mm) standard gauge Leading dia. 36 in (0.914 m) Driver dia. 62 in (1.575 m) Wheelbase 54 ft 0 in (16.46 m) Length 64 ft 8 in (19.71 m) Width 10 ft 6.19 in (3.21 m) Height 15 ft 0 in (4.57 m) over locked-down pantographs Axle load 57,500 lb (26,080 kg; 26.08 t) Adhesive weight 230,000 lb (104,300 kg; 104.3 t) Loco weight 402,000 lb (182,300 kg; 182.3 t) Fuel capacity 487 US gal (1,840 L; 406 imp gal) (for train heat boiler) Water cap. 2,041 US gal (7,730 L; 1,699 imp gal) (for train heat boiler) Electric system/s 11 kV AC @ 25 Hz Current pickup(s) Pantograph Traction motors Westinghouse, 625 hp (466 kW), eight off
Performance figures Maximum speed 100 mph (160 km/h) Power output 5,000 hp (3,700 kW) Tractive effort 18,750 lbf (83.4 kN) at 100 mph (160 km/h)
Career Numbers 4800, later 4899, later 4999 Retired 1959 Scrapped 1959

The Pennsylvania Railroad's class R1 comprised a single prototype electric locomotive constructed in 1934 by the Baldwin Locomotive Works of Philadelphia, Pennsylvania, USA, with the electrical equipment by Westinghouse.

It was built as a competitor to the GG1 design, but after trials the GG1 was selected for volume production on the basis of its superior tracking and riding qualities; the R1 prototype, however, remained in service. It was numbered 4800 originally, swapped numbers with the victorious GG1 prototype to #4899, but was moved in May 1940 to #4999 to make room for the expanding GG1 fleet.

For many years, the R1's regular duties involved hauling the westbound Broadway Limited and returning eastward with a mail and express train. The long rigid wheelbase of the locomotive caused occasional derailments in Sunnyside Yard and elsewhere. The R1 was withdrawn from service and sent for scrap in 1958.

The R1 design had four driven axles in a rigid locomotive frame, like a steam locomotive. Each was driven by two 625-horsepower (466 kW) traction motors driving the wheels through a quill drive and sprung cups. Each end of the double-ended locomotive has a four-wheel truck to guide the locomotive at speed, giving the R1 a 4-8-4 wheel arrangement in the Whyte notation (AAR: 2-D-2; UIC: 2'Do'2). In many respects the design resembled the earlier, lighter P5, but with an extra driving axle and lower axle loads.