Pennsylvania Railroad class Q1

PRR Q1
Type and origin
Power typeSteam
BuilderPennsylvania Railroad
Serial numberAltoona 4383
Build date1942
Total produced1
Specifications
Configuration:
 • Whyte4-6-4-4
Gauge4 ft 8+12 in (1,435 mm) standard gauge
Leading dia.36 in (914 mm)
Driver dia.77 in (1,956 mm)
Trailing dia.1st wheel: 45 in (1,143 mm),
2nd wheel: 50 in (1,270 mm)
WheelbaseCoupled: 26.83 ft 6 in (8.33 m),
Loco: 54.83 ft 4 in (16.81 m),
Loco & tender: 103.83 ft 9+14 in (31.88 m)
Length122 ft 9+34 in (37.433 m)
Adhesive weight354,700 lb (160,890 kg)
1st driver: 73,700 lb (33,430 kilograms; 33 tonnes),
2nd driver: 72,100 lb (32,704 kilograms; 33 tonnes),
3rd driver: 70,200 lb (31,842 kilograms; 32 tonnes),
4th driver: 68,800 lb (31,207 kilograms; 31 tonnes),
5th driver: 69,900 lb (31,706 kilograms; 32 tonnes)
Total weight1,027,870 lb (466,230 kg)
Fuel typeSoft coal
Fuel capacity82,640 lb (37,485 kg)
Water cap.19,167 US gal (72,550 L; 15,960 imp gal)
Boiler pressure300 psi (2.1 MPa)
Heating surface:
 • Firebox580 sq ft (53.9 m2)
 • Total surface7,808 sq ft (725.4 m2)
Superheater:
 • Heating area2,290 sq ft (212.7 m2)
Cylinders4
Front cylinder23 in × 28 in (584 mm × 711 mm)
Rear cylinder19+12 in × 26 in (495 mm × 660 mm)
Valve gearWalschaerts
Performance figures
Maximum speedAt least 70 mph (113 km/h)
Power output6,000 hp (4,500 kW)
Tractive effortLocomotive: 81,793 lbf (363.83 kN)
Booster: 11,250 lbf (50.04 kN)
Total: 93,043 lbf (413.88 kN)
Factor of adh.4.34
Career
OperatorsPennsylvania Railroad
Numbers6130
DispositionWithdrawn 1949, scrapped 1952

The Pennsylvania Railroad class Q1, #6130, was a single experimental steam locomotive designed for dual service. The locomotive entered service in 1942, and retired in 1949 after accumulating a relatively low 165,000 service miles.

The Q1 had a 4-6-4-4 wheel arrangement, consisting of a four-wheel leading truck, two sets of driving wheels (six and four) in a rigid locomotive frame, and a four-wheel trailing truck. The first group of six driving wheels were powered by a pair of conventional front-mounted cylinders, while the rear four driving wheels had their cylinders mounted behind them, on either side of the firebox.[1] The driving wheels were 77 in (1.956 m), larger than the PRR's existing dual-service locomotives.

The Q1's streamlined design consisted of a blunt nosecone in front of the smokebox, extended side skirts covering the locomotive's pipework, and a streamlined shape on the tender similar to the PRR's S1, S2, and T1 passenger locomotives. The cab front was set at a rakish angle. While the overall design reduced drag compared to the PRR's existing J1 class, the streamlining was ultimately removed around 1944, due to the minimal benefits at low freight speeds, and increased maintenance costs.

The Q1 was ultimately considered a failure by both PRR and later rail historians. Between design shortcomings and high operational costs, particularly during increasing use of diesel locomotives, it was never approved for series production. Despite being designed as a dual-service locomotive, minimal evidence suggests it ever served in a passenger capacity. However, its design did inspire the moderately successful albeit short-lived PRR class Q2.

  1. ^ Staufer, Alvin (1962). Pennsy Power. Staufer. pp. 216–225. LOC 62-20872.