Oi1
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Oi1-29 + 20C1-? (Schwartzkopff
3450/1905), the sole surviving P6.
Class 370-1
side drawing; source: TB vol.1 (© Lokomotiv-Revue).
KPEV Cöln 21 (Hohenzollern 1541/1901), the prototype of what later became KPEV class P6. Location and date
unknown, probably a factory photo. From my collection.
KPEV Frankfurt 604 (BMAG
3240/1903), later Frankfurt 2105, Königsberg 2204 and finally DRG 37 005. This engine was
withdrawn in December 1933. Source: Die
Lokomotive August 1904 via www.de.wikipedia.org.
KPEV Cöln 25 (Hohenzollern 1677/1904) later became Cöln
2105. Location and date unknown. After the war it was taken over by Belgian
railways, but scrapped in 1924. Source: Die
Lokomotive November 1920.
DRG 37 114 (KPEV Magdeburg
2113, then Königsberg 2161, Hanomag 5257/1908),
photographed in Großgarten in East Prussia (now Pozezdrze, Poland), probably before 1938. Withdrawal date
is unknown. Source: www.commons.wikimedia.org.
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First
locomotive with steam superheater, Prussian
Hannover 74, was completed by Vulcan in 1898 and advantages of such
layout soon became obvious. Robert Garbe, perhaps
the best known German locomotive designer, was a keen advocate of
single-expansion engines running on superheated steam, which compared to
compounds offered economy and simplicity. He managed to persuade railway
officials to order for Prussian state railways KPEV (Königlich Preußische Eisenbahnverwaltung) a universal locomotive with the
1-3-0 axle arrangement for light express and mixed traffic, capable also of
hauling freight trains on secondary lines. Intended versatility resulted in
untypical diameter of drivers: it was set at 1550 mm, while Prussian
passenger and freight engines of that time typically had 1750 mm and 1250 mm
drivers, respectively. Prototype
(Cöln 21, Hohenzollern 1541/1901) with
chamber-type superheater began tests in May 1902
and results were considered satisfactory, although at higher speed running
qualities left something to be desired. Second engine, built by Schwartzkopff in 1903, and subsequent examples had
drivers diameter increased to 1600 mm and cylinder bore from 520 to 540 mm.
Some had Pielock steam dryer instead of superheater, while others had Lentz poppet valves instead
of more typical Heusinger valve gear; both these
novelties were later discarded due to poor reliability. In 1906 new tube-type
Schmidt superheater was introduced and all earlier
examples were later brought up to this standard. With new designation system
introduced by KPEV in 1906, new machine was classed P6. Compared to
class P7, introduced slightly earlier and derived from Badenian
class IVe (saturated steam and four-cylinder
compound engine), P6 proved more economic and much less demanding from the
point of view of operation and maintenance. Production continued until 1909
and totaled 272 machines for KPEV (some sources give 271, probably
excluding the prototype). They were built by Hanomag
(90), Henschel (37), Hohenzollern
(5), Humboldt (25), MBG Karlsruhe (4) and Schwartzkopff (111). Further three (two in
1913 and one in 1916) were built by Linke-Hofmann
for military railways (Königlich Preußische Militär-Eisenbahn).
All these engines usually ran with 2’2’T16 four-axle tenders. P6
was a modern and powerful machine, but weight distribution was not perfect.
First coupled axle took higher load that the second, driven axle (15.2 and
14.9 tonnes, respectively) and running was somehow
uneasy at higher speed. However, P6 had a tractive effort of 9 150 kG, while older P41 and P42 with
two coupled axles yielded only 5 800 and 5 700 kG,
respectively, with marginally lower axle load. The choice was obvious, but
substantial improvement of the running qualities was achieved only with next
passenger locomotive for KPEV – the famous P8, also designed by Garbe. After
WWI, Prussian railways kept 160 engines plus three from military railways
(all later absorbed by DRG and classed 370-1); until 1923
almost all had been transferred to East Prussia. Although P6 was, by Prussian
standards, not a very numerous class, it found quite widespread use in
post-war Europe, in France (16), Belgium (16), Italy (9), Lithuania (LG
class K6, 5) and Latvia (LDV class Bn, 4, service
numbers 51 through 54). Three went to Alsatia, to
be taken over later by French railways, and four to Saarbahn,
to be absorbed by DRG in 1935 as 37 164 through 167. According to the
monographic article in SK, mentioned in the References, the ultimate
fate of two machines remains unknown. Poland had the second largest fleet of
P6s – in all, 44 engines were taken over after the war and classed Oi1 in
1923. Initially all were assigned to the regional management in Wilno. In 1936 fifteen were transferred to the regional
management in Radom in central Poland, but were based in Lublin and Chełm. No wonder, thus, that in September 1939 most Oi1s
(36) fell into Soviet hands. Initially Soviet ministry of transport (NKPS)
retained their Polish service numbers, written on cabs in Russian script.
Lithuanian and Latvian engines were also impressed into the NKPS
service after these countries were occupied in June 1940; these included
Oi1-19 (ex KPEV Erfurt 2109, BMAG 3729/1907), evacuated to
Lithuania in September 1939 and impressed into service as K6 106. As many as
22 ex-P6s were rebuilt for the 1524 mm track. In September 1939 Germans
captured only six engines, impressed into the DRG service as 37 168
through 173. More, however, came later. After Fall Barbarossa Germans
captured 34 ex-Polish Oi1s; they were designated 37 174 through 200 and 37
251 through 254 (numbers 37 201 through 206 were assigned to class G6
engines, operated by Lübeck-Büchener Eisenbahn, formally taken over by DRG in 1938,
while 37 255 through 257 were ex-Lithuanian and Latvian engines, taken over
by NKPS in 1940 and captured by Germans in 1941). Two were operated by
Ostbahn with original service numbers, plus
ex-LG 106 (after WWII the latter machine remained with DR and
was re-numbered 37 106II). The fate of Oi1-4 and Oi1-31 is
unknown. According to Die Baureihe 370-2
(see References), one of these engines was withdrawn in 1936 and the other
one was captured by the Soviets in 1939. Only
fifteen ex-PKP engines were returned immediately after WWII, but they
were joined by one ex-Lithuanian (LG
K6 103), one ex-French and eighteen ex-DRG machines, as well as
pre-war Oi101-12 (from Austro-Hungarian Heeresbahn),
erroneously designated Oi1-4. Of these, five examples (including pre-war
Oi1-25, and Oi1-44) most probably saw no service and were written off in
1946, so post-war class numbering ran up to Oi1-31 (Oi1-4 was later
re-designated Oi101-2). Two ex-PKP engines
returned by DR in 1956 (Oi1-21 and Oi1-33) were scrapped with no new
service numbers assigned. Oi1s were used mainly with local passenger trains
in northern Poland; most were assigned to the Gdańsk
regional management. Until 1957, seventeen were withdrawn, but the rest
survived until late 1960s and the last one (Oi1-6, Schwartzkopff
3635/1906, KPEV Bromberg 2103, then Oi1-11 and DRG 37 190)
was withdrawn in March 1972. Ex-PKP
Oi1s that remained in the Soviet Union, together with those acquired as war
booty, survived in service until early 1950s. After the war they were classed
TN (TH in Russian script), but it is not known if all examples were actually
re-numbered. In late 1940s many went to industry. Oi1-29
(Schwartzkopff 3450/1905, KPEV
Elberfeld 2110, then Oi1-7 and DRG 37 171), withdrawn in July 1968,
has been preserved at the Railway Museum in Warsaw. This is the sole
surviving locomotive of this type. Main
technical data
1) Including 272 for KPEV and three for
military railways; some sources give 271 for KPEV (probably excluding the prototype).
2)
Other sources give 131.58
m2. List of vehicles can be found here.
References
and acknowledgments
-
Monographic article by Roman Witkowski
(SK vol. 3/1999); -
Ingo Hütter’s website www.lokomotive.de/lokomotivgeschichte/datenbank;
-
LP; -
Die Baureihe 370-2 by Thomas Samek (EK
Verlag, 2006). |
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