Prussian P 6

The Prussian Class P 6s were passenger locomotives operated by the Prussian state railways with a leading axle and three coupled axles.

Prussian P 6 DRG Class 37.0–1 PKP Oi1
Oi1-29 ex 37 171
Number(s)	DRG 37 001–163
Quantity	275
Manufacturer	Hohenzollern, Schwartzkopff
Year(s) of manufacture	1902–1910
Retired	about 1950
Wheel arrangement	2-6-0
Axle arrangement	1'C h2
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge
Length over buffers	17,608 mm (57 ft 9 1⁄4 in)
Service weight	57.1 t (56.2 long tons; 62.9 short tons)
Adhesive weight	44.6 t (43.9 long tons; 49.2 short tons)
Axle load	15.2 t (15.0 long tons; 16.8 short tons)
Top speed	90 km/h (56 mph)
Indicated Power	755 kW (1,012 hp)
Driving wheel diameter	1,600 mm (62.99 in)
Leading wheel diameter	1,000 mm (39.37 in)
No. of cylinders	2
Cylinder bore	540 mm (21.26 in)
Piston stroke	630 mm (24.80 in)
Boiler Overpressure	12 bar (1,200 kPa; 170 psi)
Grate area	2.28 m2 (24.5 sq ft)
Superheater area	41.91 m2 (451.1 sq ft)
Evaporative heating area	134.93 m2 (1,452.4 sq ft)
Tender	pr 2'2' T 16
Water capacity	16.0 m3 (3,500 imp gal; 4,200 US gal)

The P 6 was conceived as a so-called universal locomotive. The first vehicle was manufactured in 1902 at Düsseldorf by the firm of Hohenzollern. This engine has a number of features that are characteristic of its designer, Robert Garbe: a narrow chimney located well forward and the unusual position of the boiler. As a result, and in spite of the relatively small, 1,600 mm (62.99 in) diameter, driving wheels (on the prototype they were only 1,500 mm or 59.06 in), the locomotives were authorised to travel at up to 90 km/h (56 mph), a speed which could not be attained in practice due to its poor riding qualities.

The smokebox superheater installed on the first machines was soon replaced by a smoke tube superheater. In all, 275 engines of this class were built up to 1910. 110 examples had to be handed over after the First World War as reparations. 163 locomotives were taken over by the Deutsche Reichsbahn as DRG Class 37.0-1, where they were allocated the running numbers 37 001–163. The locomotives with numbers 37 201–206 were, by contrast, G 6 and P 6 class engines respectively of Lübeck-Büchen Railway (LBE), that had a different design from the Prussian locomotives.

The Prussian P 6s were retired by about 1950. The few engines left after the Second World War were no longer employed by the Deutsche Bundesbahn and the Reichsbahn.

The locomotives taken over by the Polish State Railways (PKP) were given the designation Oi1. One of them has been preserved and can be viewed in the Warsaw Railway Museum. The engines were equipped with Prussian tenders of class pr 2'2' T 16.