OKi2
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Oki2-27, Jaworzyna Śląska loco depot,
August 4, 2004…
…and the same engine after external refurbishment,
photographed on
DRG
74 533 (ex ‘Elberfeld 7724’), Borsig
6136/1907, somewhere in
Class 744-13 side drawing, © Lokomotiv-Revue; source: TB vol.2.
A drawing from the LHW
catalogue card shows LBE
No.137 (Linke-Hofmann
2151/1920). This engine later became 74 1316; after brief service in The
Netherlands in 1946 was transferred to DB
and written off in 1958. From my collection. |
Between 1903 and 1910, Prussian state railways KPEV received 470 class T11 tank engines for passenger traffic with the 1-3-0 axle arrangement. They were designed by renowned Robert Garbe and served mainly in the Berlin area with the S-Bahn. These locomotives ran on saturated steam and had the tractive effort of 8.6 tonnes. Even before the deliveries of production examples began, a variant with steam superheater had been conceived and first four engines of this type were built by Union-Gießerei of Königsberg in 1902. After some design changes they were ordered in series in 1905 as class T12 – just as their predecessors, mainly for the S-Bahn. First 72 examples were fitted with chamber-type superheater in the smokebox. Later, a 33.4 sq.m Schmidt-type superheater with individual sections located in smoke tubes was introduced and earlier examples were brought up to this standard during overhauls. Externally T12 resembled its predecessor, the main differences being the smokebox larger in diameter than the boiler and slightly shorter waterboxes. Steam pressure remained at 12 bar, but due to larger cylinders (diameter increased from 480 to 540 mm) tractive effort was higher by 0.6 tonne. This engine could haul a 300-tonne draft on a 3‰ grade at 60 km/h; due to the lead Krauss-Helmholtz truck, running qualities were good even at the maximum speed of 80 km/h. Until 1921, KPEV received
974 T12s, of which the majority – possibly about 500 – went to the S-Bahn.
Most were built by Borsig, the rest came from Union, Grafenstaden
and Hohenzollern. During the production run, many minor design
modifications were introduced. At least forty more engines were supplied to
other German railways; some of them differed in certain details. After WWI,
newly-formed DRG took over 899 ex-KPEV engines, which were
classed 744-13 and given service numbers 74 401 through 1300 (with
the exception of 74 544). Further ten, initially based at Saarbrücken and in
1920 impressed into Saarbahnen, were taken over by DRG as 74 1301 through 1310 when
the Saar region was incorporated into the German Reich in 1935. Finally, in
1938, DRG took over eleven T12s built for the Lübeck-Büchener
Eisenbahn (LBE) by Linke-Hofmann in three small batches in
1914, 1920 and 1923. These engines had been given LBE service numbers
132 through 142 and became DRG 1311 through 1321; the differed in some
details and were longer by 280 mm. Electrification
of the S-Bahn, which started in 1924 and was basically completed until
1933, made many engines of this type surplus. They were moved to secondary
local lines or relegated to switching. After WWII they remained in service
with both DB and DR until 1968; some went to industry. Relatively
few T12s were impressed into the PKP service after WWI. Classed OKi2,
they numbered just twelve examples, plus six more in Gdańsk; the latter had
service numbers OKi2-1Dz through 6Dz, where ‘Dz’ stood for ‘Danzig’. All had
been previously assigned to KPEV regional managements (KED) in
Danzig (Gdańsk) or Kattowitz (Katowice). They remained in use until 1939 and
after the September campaign were absorbed by DRG with new service
numbers 74 1322 through 1338 (OKi2-1 was probably not restored in service and
its subsequent fate is not known). Of these, thirteen were returned after the
war, but PKP received many more engines of this type as a part of war
reparations, so post-war class OKi2 numbered as many as 84 examples. All were
assigned to the regional management in Poznań and remained in use with local
trains and as switchers until early 1970s. Few of them, after withdrawal, went
to industry and the last example remained in use at the ZNTK (Railway
Stock Repair Works) in Łapy until 1980. This engine (Borsig
9527/1916, KPEV ‘Berlin 8707’, then DRG 74 1234 and finally
OKi2-27) was in 1985 transferred to the Railway Museum of Warsaw and later
went to the Jaworzyna Śląska depot (now Industry and Railway Museum).
Recently externally refurbished, it remains on static display. As far as I
know, two more T12s still exist, both in Main technical data
1)
Some sources give 974, which refers to the output
for KPEV only. 2)
After WWII. 3)
Some sources give 105.37 sq.m or 108.0 sq.m, which may
refer to various versions. References and acknowledgments
Concise
information can be found in TB vol.1 and LP. |
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