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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) |
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. 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 late 1930s fifteen were transferred to Radom in
central Poland. No wonder, thus, that in September 1939 most Oi1s (35) fell
into Soviet hands. Soviet ministry of transport (NKPS) retained their
Polish designations, 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 and ex-LG 106 was probably not
re-numbered (after WWII this machine remained with DR as 37 106II).
The fate of Oi1-4 and Oi1-31 is unknown (probably they were captured by the
Soviets, but this has not been confirmed). 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) 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 Gdañsk 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; later 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. References and acknowledgments
-
Monographic article by Roman Witkowski (SK
vol. 3/1999); -
Ingo Hütter’s website www.lokomotive.de/lokomotivgeschichte/datenbank;
-
LP. |
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