Prussian S 9

The Prussian S 9 was an express steam locomotive with the Prussian state railways, first built in 1908. It had a 4-4-2 (Atlantic) wheel arrangement and a four-cylinder compound engine. It was developed by the firm of Hanomag in Hanover who delivered a total of 99 engines of this class.

Prussian S 8, S 9
DRG Class 14.0
Number(s)DRG 14 001, 002, 031
Quantity99 (2 were "S8"s)
Year(s) of manufacture1908ff.
Axle arrangement4-4-2
Axle arrangementS 8: 2'B1' h4v
S 9: 2'B1' n4v
TypeS 8: S 2/5 h4v
S 9: S 2/5 n4v
Track gauge1,435 mm (4 ft 8 12 in)
Length over buffers21,860 mm
Length13,110 mm (excl. tender)
Overall wheelbase10,750 mm
Empty weight68.0 t
Service weight74.7 t
Adhesive weight33.0 t
Axle load16.5 t
Top speed110 km/h
Coupled wheel diameter1,980 mm
Leading wheel diameter1,000 mm
Trailing wheel diameter1,250 mm
No. of cylinders4
LP cylinder bore580 mm
HP cylinder bore380 mm
Piston stroke600 mm
Boiler Overpressure14 bar
No. of heating tubes272
Heating tube length5,200 mm
Grate area4.00 m2
Radiative heating area14.10 m2
Tube heating area222.00 m2
Evaporative heating areaS 8: 229.71 m2
S 9: 182.54 m2
Tenderpr 2'2' T 21.5/30/31.5
Water capacity21.5/30.0/31.5 m3

There were also some high-speed trials locomotives which were classified as S 9s, but did not belong to this particular class. These included two cab-forward 4-4-4 locomotives Altona 561 and 562.

Although at the time superheated technology was widespread, the state of Prussia still wanted to have saturated steam engines delivered by Hanomag. The locomotives procured as a result had a very powerful boiler and, at 4 m2, the largest grate area of any Prussian steam locomotive. The quantity of steam generated was however more than the high-pressure cylinders could cope with. As a result, the performance of the S 9 was little better than the considerably smaller superheated locomotive, the Prussian S 6. Nevertheless, the S 9 initially formed the backbone of express train services from Berlin to Hanover. Like all German Atlantic locomotives, the S 9 quickly proved too underpowered for the increasingly heavy trains it had to haul.

Two locomotives (Hannover 903 and 905) were fitted with superheated boilers in 1913 and 1914 and reclassified as S 8s.

After 1919 17 locomotives had to handed over to Belgium and 4 to France. Only three of them, the two S 8s and a saturated steam engine, were taken over by the Deutsche Reichsbahn as DRG Class 14.0. The two S 8s were given numbers 14 001 and 14 002; the S 9 ("Essen 907") number 14 031. All three were retired by 1926.

The locomotives were equipped with Prussian tenders of classes pr 2'2' T 21.5, pr 2'2' T 30 und pr 2'2' T 31.5.

Belgian engines managed to outlive German engines by several years since they were only written-off in 1948. They were used on fast trains on the lines around Antwerp[1].

See also


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