OKe1

KPEV T5¹ Altona 1561 (Henschel 5737/1901), factory photo. Source: Lokomotiven der alten deutschen Staats- und Privatbahnen by Hermann Maey and Erhard Born, Transpress, 1983.

OKe1-4 (Henschel 6779/1904) in German service, Czeremcha depot, 1941 or 1942. The locomotive still bears PKP service number. Source: www.pl.wikipedia.org.

T5¹ side drawing from TB vol 2, © Lokomotiv-Revue.

KPEV Berlin 2027 (Henschel 4229/1896), location and date unknown, probably a factory photo. This engine was later re-numbered Berlin 6617; I have no information on its subsequent fate, but it was not given a DRG number. Source: Die Lokomotive December 1921.

Between 1905 and 1908 all locomotive types of Prussian state railways KPEV were re-designated within the framework of new system introduced in 1903. Tank engines were designated by capital letter T (for Tenderlokomotive) plus a number which – at least initially – indicated the power group: the higher number, the higher the power. Even and odd numbers were assigned to locomotives running on superheated and saturated steam, respectively. Both these rules were not strictly obeyed, especially later. Class T5 ultimately included as many as six distinct types (including one superheated!), which differed even in such basic features as axle arrangements, having two or three coupled axles.

By far the most numerous was sub-class T5¹. First locomotives of this type were ordered from Henschel by Berliner Stadtbahn in 1895, in order to replace older 1-2-0s and 0-2-1s (later class T2). Prototypes (4140/1895 and 4141/1895) became Berlin 2011 and Berlin 2012, respectively, and were standardized as Musterblatt III 4i, 1.Auflage. Production engines (Musterblatt III 4i, 2.Auflage) were slightly longer, albeit axle base of 6800 mm was retained, and fitted with large steam dome. Total output was 309 examples, all from Henschel, the last one being 7106/1905. Twenty more, also classed T5¹, were delivered between 1907 and 1921 by Hanomag to Großherzoglich Oldenburgische Eisenbahn. First five were very similar to production T5¹s built for KPEV, the rest had axle base increased to 7000 mm, overall length remaining unchanged.

T5¹ featured the 1-2-1 axle arrangement with leading and rear Adams axles that facilitated similar running qualities in both directions. They were thus rather versatile and found quite widespread use. With the appearance of more powerful types they were gradually relegated to branch lines and switching. Although newly-formed German state railways DRG in 1923 intended to retain as many as 115 examples in service, only 26 were actually kept, classed 71⁰. The last one, 71 021 (Henschel 7092/1905) was withdrawn in 1931. Four examples were taken over by Saarbahn, but all were written off before incorporation of Saarland in 1935. Several were sold to private railways. The machines from Oldenburg, numbered 71 401 through 71 420, were withdrawn between 1927 and 1930, so two enjoyed service life of mere nine years.

Five examples taken over by PKP were classed OKe1 and assigned to regional managements in Wilno and Białystok. Three were written off between 1936 and 1938. OKe1-2 (Henschel 5725/1901) was taken over by Lithuanian railways LG and re-numbered T₅ 801. In 1940, following the annexation of Lithuania, it was impressed into NKPS. OKe1-4 (Henschel 6779/1904) also fell into Soviet hands, but was later captured by Germans and served with DRG, but for unknown reasons was not re-numbered and retained its original PKP number. It was captured by the Soviets in July 1944. Ultimate fate of both these locomotives remains unknown. No T5¹ has been preserved.

Main technical data

No.	Parameter	Unit	Value
1.	Years of manufacture	-	1895 – 1921
2.	Total built / used in Poland	-	329 / 5
3.	Tender class	-	-
4.	Axle arrangement	-	1-2-1
5.	Design maximum speed	km/h	75
6.	Cylinder bore	mm	2 x 430
7.	Piston stroke	mm	600
8.	Engine rating	kW/hp
9.	Tractive effort	kG
10.	Boiler pressure	MPa	1.22
11.	Grate dimensions	m X m	1.57 m^2
12.	Firebox heating surface	m^2	6.6
13.	Distance between tube plates	mm	4 000
14.	Number of flue tubes	-	171
15.	Heating surface of flue tubes	m^2	88.1
16.	Number of smoke tubes	-	-
17.	Heating surface of smoke tubes	m^2	-
18.	Evaporating surface, total	m^2	94.7
19.	Superheater heating surface	m^2	-
20.	Diameter of drivers	mm	1 600
21.	Diameter of idlers front/rear	mm	1 000 / 1 000
22.	Total weight, empty	kg	41 500
23.	Total weight, working order	kg	53 100
24.	Weight on drivers, working order	kg	31 400
25.	Weight with tender, empty	kg	-
26.	Weight with tender, working order	kg	-
27.	Maximum axle load	T	15.7
28.	Axle base (with tender)	mm	6 800
29.	Overall length (with tender)	mm	11 685
30.	Brake type	-	Westinghouse

Note: all data for production locomotives for KPEV.

List of vehicles can be found here.

References and acknowledgments

- Lietuvos Geležinkelių Garvežiai 1919-1940 m. / Steam Locomotives of Lithuanian Railways 1919-1940 by Toms Altbergs (Zidex, Lithuania, 2012);

- LP, TB vol. 2;

- Lokomotiv-Archiv Preußen Band 3 by Andreas Wagner (Bechtermünz Verlag, 1996);

- www.pl.wikipedia.org;

- monographic article by Ryszard Stankiewicz (KMD vol. 1-2/2017).