OKo1
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OKo1s were often used with local trains. This engine (OKo1-11, ex KPEV Essen 8918, then DRG 78 379, Vulcan 3892/1922) was photographed by Geoff Plumb (http://geoff-plumb.fotopic.net –
thanks for permission!) near Czempin on
The sole survivor in
Another photo of
the OKo1-3, taken on
…yet another one,
taken on the same occasion...
...and cab interior.
Side drawing of the DR class 781-5
from TB vol.2.
According to my data, this picture of the
OKo1-18 was taken at the Jaworzno depot in May
1960. Photo from my collection.
TCDD
3705 (Henschel 20554/1925) at the Çamlik Buharli Lokomotif
Muzesi,
78 009, DR, Vulcan
2761/1912, somewhere in Eastern Germany, August 1971. Photo by Werner Nagel
(from my collection).
Two pictures from www.de.wikipedia.org by someone who
wishes to be known as MPW57: 78 1009-6 (Vulcan
2791/1912) with original service number 78 009, photographed in Potsdam on
May 17, 1993…
…and 78 510 (Vulcan 1972/1924) on display at the Verkehrsmuseum Nürnberg, July 14, 1985.
Most probably this is Stettin 8410 (Vulcan 2762/1912). Later 78 010,
it remained in service with DR
until 1969. Location and date unknown. Photo from my collection.
An unidentified class T18 engine, location
and date unknown. Source: Die Lokomotive December 1920.
DB 78 243 (formerly KPEV
Essen 8470, Vulcan 3769/1922),
photographed in Essen on March 12, 1960. This locomotive was withdrawn five
years later. Photo by Herbert Schambach (postcard
from my collection).
Beautifully preserved DB 78 468
(Henschel
20166/1923), Wattenscheid-Höntrop, September 17,
2016. Photo by someone who wishes to be known as Tenderlok
(source: www.commons.wikimedia.org).
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KPEV class T18 was the
penultimate one in the long line of Prussian tank locomotives. It was
intended as a replacement of older passenger tank engines (classes T10, T11
and T12), mainly with commuter and suburban trains, so ability to run at full
speed (100 km/h) in both directions was mandatory. In order to assure good
running qualities during reverse running, a rather exotic axle arrangement
2-3-2 was chosen, for the first time. Such arrangement, in Europe sometimes
referred to as Baltic, was used in
several locomotive types in Austria, France, Hungary, Spain and The
Netherlands, but none of these was particularly widespread; with a notable
exception of Hungarian class 303, all were tank engines. In North America it
was known as Hudson and appeared by
a simple extension of the Pacific with large firebox that had to be supported
by a trailing truck rather than a single axle. Compared to other North
American types, however, Hudsons were not numerous, totaling less than 500 examples
in all. In
T18, axle arrangement resulted in a long locomotive (exactly 3 m longer than
T10) of somehow peculiar appearance. Apart from this, new engine made use of
modern, but already proven design concepts. Boiler was very similar to that
of class P8 with the same moderate pressure of 12 bar. Grate was slightly
shorter and overall heating surface was reduced by a few percent. Cylinder
bore was reduced from 575 to 560 mm, but piston stroke remained unchanged,
although drivers were reduced in diameter by 100 mm. First ten examples were
built by Vulcan-Werke
of Stettin (today Szczecin) and delivered in late 1912 (serial numbers 2753
through 2762). During service tests, T18 proved itself a good and tough machine,
capable of hauling even light express trains: with a 350-tonnes draft, 90
km/h could be easily maintained. Initially running qualities were found not
entirely satisfactory and maximum speed was set at 90 km/h. After some
corrections of wheelsets balancing and resultant improvement it was increased
to 100 km/h. KPEV were entirely
satisfied with their new acquisition and in 1914 ordered it in quantity.
Production engines differed from first ten examples in being fitted with feedwater heater. Until
the end of the war, about 140 examples were accepted by KPEV, all built by Vulcan.
Production against KPEV orders
continued until 1923; in all, 332 engines were given Prussian service numbers
(last of them was ‘Essen 8960’, Vulcan
3916/1923). Apart from these, Vulcan
in 1915 built 28 T18s for the state railways of then-German Alsace-Lorraine;
after WWI they were taken over by SNCF
as class 232TC. From the above-mentioned fleet of KPEV machines, nineteen (assigned to KED Saarbrücken) were in 1920
transferred to the Saarbahnen.
Two were transferred to Belgian railways and numbered 9403 and 9408; both
were withdrawn before 1925. The rest were incorporated into newly-formed Deutsche Reichsbahngesellschaft
(DRG) as class 781-5; in
1925, they were allocated serial numbers 78 001 through 145, 78 166 through
282 and 78 351 through 401. Between 1923 and 1925, 122 more were built
against DRG orders by Vulcan (69) and Henschel (53), later designated
78 402 through 523; five more were built by Vulcan at own risk in 1924 and purchased by DRG in 1927 to become 78 524 through 528. Moreover, 27 examples
were built for Saarbahnen
by Vulcan, Henschel, Hanomag and Société Franco-Belge de Matériel
de Chemins de Fer of La Croyère,
Belgium; when the Saar region was incorporated into the German Reich in 1935,
all T18s owned by Saarbahnen
were taken over by DRG as 78 283
through 328. In
1919, Württembergische Staatsbahn
ordered twenty T18s from Vulcan
(serials 3513 through 3532, service numbers 1121 through 1140); after all
German railways were merged into DRG,
they became 78 146 through 165. Last machines of this type were, quite
surprisingly, built in late 1930s, when private Eutin-Lübecker Eisenbahn
(ELE) ordered a single example from
Henschel (23241/1936). Due to its satisfactory
performance, in particular high tractive effort combined with moderate axle
load, second engine was ordered three years later (24563/1939); it differed
from its predecessor in having two sand domes instead of one, Knorr-Tolkien feedwater pump and in some minor details. On January 1,
1941, these two engines were taken over by DRG as 78 329 and 78 330. This gives a grand total of 536
examples built for various German railways, of which 508 were included in the
DRG rosters – as far as I know, no
French 232TC was impressed into German service during WWII. Further eight,
with slightly modified boilers, were ordered by Turkish CFOA (Société de Chemins de Fer
Ottoman d’Anatolie) railways. They were built
by Henschel
in 1925 (serials 20550 through 20557), but delivered to newly-formed TCDD railways and given service
numbers 3701 through 3708. Four
DRG engines of this type were
written off before the end of the WWII; two of them, 78 184 and
78 191, were later taken over by PKP
and restored in service. Of remaining 504 examples, the majority – 416 – went
to DB. Several were withdrawn
immediately afterwards, but 409 remained in use. Compared to other steam
locomotives, their service was quite long: last of them, 78 246 (Vulcan 3772/1922) was written off in
December 1974. DR were left with 53
machines; most were written off in early 1960s and the last, 78 427 (Vulcan 3922/1923) survived in service
until August 1971. Four examples were taken over by the Soviets and
re-numbered 77.xxx (where xxx stood for DRG
number); they probably saw very little service, if any. Czechoslovakian
railways ČSD acquired (according to
www.beitraege.lokomotive.de)
two machines, which were not restored in service (78 280 and 78 376) and had no
class designation assigned; EZ
confirms only the first of them, scrapped in 1952. Three more (78 131,
78 168 and 78 495), also with no ČSD numbers assigned, were transferred to PKP in August and September 1945. No
machine of this type served with PKP
before WWII, but after 1945 twenty-nine were acquired and impressed as class
OKo1. Most of them had been built by Vulcan,
except OKo1-22, which was built by Franco-Belge for Saarbahnen (s/n 2385/1925, service number 8444, later DRG 78 326). All were assigned to the Poznań District Management and remained there throughout
their service. They were used mainly with local and suburban trains and
enjoyed a good opinion. Their performance was similar to that of Ok1
(ex-Prussian P8), tractive effort was almost the same and ability to run at
full speed in both directions made them particularly suitable for secondary
lines, where many terminal stations had no turntables. Later they were
supplemented by indigenous TKt48s, but soldiered on until early 1970s. On
January 1, 1971, twenty-two were still in service and last four, OKo1-15,
-16, -19 and -23, survived until 1975. According to SK, four trucks from scrapped OKo1s are still used for works
transport at the ZNTK (Railway
Stock Repair Works) in Ostrów Wielkopolski. One
engine has been preserved: OKo1-3 (Vulcan
3610/1920, KPEV Essen 8428, then 78
189), withdrawn in September 1972, it can be seen on static display at the
Railway Museum in Warsaw. Further five T18s have been preserved in Germany
and TCDD 3705 (Henschel 20554/1925) can be
seen at the Çamlik Buharli Lokomotif Muzesi (Çamlik steam locomotive museum) in Turkey. Main technical data
- Plus
eight slightly different engines for Turkey. - Some
sources erroneously give 31. - Some
sources give 138.3 m2. - 90
km/h in first ten examples. List of vehicles can be found here. References
and acknowledgments
-
http://www-personals.umich.edu/~khmiska
(website by Kurt H. Miska, unfortunately no longer
active); - TB vol.2; - Lokomotiv-Archiv
Württemberg by H. Lohr and G. Thielmann, Transpress, Berlin, 1988; -
SK, various issues; -
www.beitraege.lokomotive.de
(locomotive database by Ingo Hütter); -
Monographic article by Ryszard
Stankiewicz (SS
vol. 144). |
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