Prussian S 4

4 ft 8+1⁄2 in)Leading dia.1,000 mmDriver dia.1,980 mmLength:
​ • Over beams18,210 mmAxle load16.0 tAdhesive weight31.9 tService weight50.2 tWater cap.13.0/15.0/16.0 m³Boiler:
​No. of heating tubes115No. of smoke tubes18Heating tube length4,300 mmBoiler pressure12 barHeating surface:​ • Firebox2.32 m² • Radiative10.65 m² • Evaporative117.70 m²Cylinders2Cylinder size540 mmPiston stroke600 mmValve gearWalschaerts (Heusinger, outside)

Performance figures
Maximum speed	100 km/h
Indicated power	736 kW

Career
Numbers	DRG 13 501–504
Retired	1927

Data for production series

The Prussian S 4's were German superheated express steam locomotives with the Prussian state railways, later grouped as DRG Class 13.5 in the Deutsche Reichsbahn. They were an evolutionary development of the Prussian S 3. The first locomotive was built in 1898 by Vulcan, Stettin as a modified S 3. She was the first superheated locomotive in the world.^[1] She was initially designated as Hannover 74 and towards the end as the S 4 Cassel 401. Two further trials locomotives appeared in 1899 and 1900 as Hannover 86 and Berlin 74 also classed as S 3's. They were later reclassified as S 4's Hannover 401 and Posen 401.^[1]

Not until the teething troubles had been resolved was the S 4 put into series production in 1902 in Borsig, from 1906 also in Henschel and Humboldt.^[1] Unlike the prototypes the production engines were developed independently of the S 3, and 104 examples were built in the years to 1909 when procurement was halted in favour of the Prussian S 6. Up to 1906 a smokebox superheater was installed; afterwards smoke tube superheaters were used.^[1]

The S 4's star waned even before the First World War, so that within a few years most of the engines had disappeared from the tracks. The remainder were employed on passenger train or even goods train duties.

In 1923 the Deutsche Reichsbahn recorded 44 S 4's in its provisional renumbering plan as 13 501-544. But by 1925 only four of them were left. These were given running numbers 13 501–504 in 1925^[1] and were retired by 1927.

After the First World War, six locomotives were given to the Polish State Railways (PKP), where they were classified as Pd2 class, numbers 1 to 6.^[1] During the Second World War five S 4s came into the Reichsbahn holdings from Poland as 13 401–405.^[1] Two of them were eventually given back to Poland in 1955 by the DR.

The locomotives were equipped with tenders of Prussian classes pr 2’2’ T 16, pr 3 T 13 and pr 3 T 15.

See also

• Prussian state railways
• List of DRG locomotives and railcars
• List of Prussian locomotives and railcars

References