Ok22
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Ok22-23 (Fablok
339/1929) at Jaworzyna Śląska depot (now Industry
and Railway Museum), photographed on
Ok22-31 (Fablok
356/1929) at Wolsztyn depot, photographed on
Side drawing of the Ok22 from PNP.
On
Next year, on More pictures of this engine, taken at the 2008
Show, can be seen here.
Ok22-165. My data give ‘location unknown, April
1959’, but judging from the service number this is a pre-war picture. Photo
from my collection. |
First
passenger locomotive, designed and built for PKP after WWI, was patterned upon Prussian P8 – a very successful
machine, built in almost 4,000 examples between 1906 and 1940 and used in
many European countries. Poland acquired 192 P8s as a part of war reparations
and bought 65 brand new machines from Linke-Hofmann, Hanomag
and Schwartzkopff between 1921 and 1923; all these locomotives were
classed Ok1. More examples were taken over after WWII and Ok1 remained in
service until 1980 as the most numerous class of passenger locomotives with PKP. Polish
development of P8 was designated Ok22 and first five machines (Ok22-1 to
Ok22-5) were built in 1923 by Hanomag. After extensive tests and some
modifications, production was undertaken by the First Locomotive Factory
in Poland (Fablok) of Chrzanów in 1928, first example (Ok22-6, s/n
275/1928) being delivered in December. Until 1934, 185 machines were built
there. Main
differences between P8 and Ok22 concerned the boiler which, however, remained
a fairly conservative design. In order to burn low-grade coal, boiler was
raised by 400 mm to accommodate larger firebox (grate was shorter by 260 mm,
but wider by 690 mm, its area being increased from 2.65 to 4.01 m2).
Number of flues was increased from 119 to 175 and of smoke tubes – from 26 to
28. Evaporating surface was larger by over 28%, but superheater heating
surface – only by less than 8%; with unchanged boiler pressure of only 12 bar
and the same dimension of cylinders, overall efficiency was slightly below
that of P8. Locomotive frame, steam engine and motion gear remained virtually
unchanged. Machines built by Fablok had different driver’s cabs
(similar to that of Ty23) and two boiler domes. They were coupled with 22D23
four-axle tenders (again from Ty23) which, compared to 22D2s of Hanomag-built
examples, had slightly lower empty weight, but were longer and had coal box
capacity increased from 7 to 10 tonnes. Between
two world wars, Ok22 was one of the most important classes in PKP service, used throughout the
country (five machines, Ok22-151 to Ok22-155, were leased to the French-Polish
Railway Company for passenger traffic on the Coal Trunk Line between
Upper Silesia and Gdynia). Until the introduction of Pt31, they were also
commonly used with express trains (more powerful Os24 had poor running
qualities at higher speed). In-service modifications, apart from fitting
electric lighting from 1931 onwards, were rather few. 55 machines were fitted
with Langer device (air and steam jets directed into firebox to improve
combustion). Five examples (Ok22-117 through Ok22-121) were fitted with Lentz
valve gear which, although successful, proved somehow troublesome in
maintenance and has not found widespread use. Several machines had Dabeg or
Worthington feedwater pumps instead of standard Metcalfe-Friedmann
exhaust-steam injectors. Ok22-23 was in 1935 experimentally fitted with
Nicolai-type piston valves. According to PNPP,
55 engines were fitted with Langner or Pyran devices for smoke-less
combustion, which proved completely unsuccessful and were soon removed. In
1939, Ok22s shared the fate of other Polish locomotives. 111 examples
captured by Germans were impressed into Ostbahn service and classed 3845-46
from 1941. 78 engines were captured by the Soviets. One (Ok22-132) went with
an evacuation train to Lithuania and was absorbed by state LG railways as K9-41, to fall into
Soviet hands in 1940 (according to PNPP,
this machine was destroyed in Wilno by a direct bomb hit in June 1941). Most
Soviet engines were converted to 1524 mm track and served in Western Ukraine
and Byelorussia, first converted example (in November 1939) was Ok22-100, and
59 more followed until 1941; after German attack most of them were sent
eastwards. According to some sources, a few examples were evacuated to
Romania in 1939, but I have found no trace in either PNPP or Romanian sources. After Fall Barbarossa, 21 Soviet
engines fell into German hands, of these, eighteen were impressed into DRG. Some locomotives serving with Ostbahn
were later, as the fortunes of war changed, captured by the Soviets, but only
one (ex Ok22-42), which had served with NKPS
before 1941, was retained, as it was considered Soviet property. In 1945, Polish administration initially took over 59 machines, of which 51 were restored in service and given new numbers. Four more were returned by ČSD and two by ÖBB in 1947 and 1948; this given a total of 57 engines. As with many other pre-war classes, not a single engine returned from the Soviet Union. In 1955, 30 Ok22s were re-vindicated from Eastern Germany, but they were all in a very poor condition and immediately went for scrap, although according to some sources they were given new service numbers. This is confirmed by the fact that three Ok55s after impression into this class (see below) were given service numbers from 89 onwards. Over 30 examples were withdrawn and scrapped in Western Germany in the 1950s. Soviet Ok22s remained in use until mid-1960s, later some went to industry. After introduction of Ol49, Ok22s were gradually shifted to local traffic, but occasionally hauled even long-distance trains until late 1960s. Post-war modifications were few and typical – steel fireboxes, standardized injectors and boiler fittings and lighting (apart from 25 engines, all pre-war Ok22s were fitted with gas lighting). Few examples were withdrawn before 1975, but afterwards they fell in number quite quickly. Last of them survived in service in Lower Silesia until November 1979. In
1952, two Ok22s were reboilered with boilers taken from Tr203s (ex-USATC S160 engines, supplied after
WWII). According to some sources, these were Ok22-35 and Ok22-45, but other
sources suggest that these might have been wrecked undercarriages with no
service numbers assigned. Designated Ok203 and later Ok55, they were joined
by third example – which did not use an Ok22 undercarriage – in 1959. This
reconstruction proved entirely successful, as Tr203 boilers were much more
modern and efficient; plans for further conversions were, however, abandoned.
These hybrids were in October 1970 impressed into Ok22 class and
re-designated Ok22-89 to Ok22-91, to be written off between 1976 and 1978 and
scrapped. Ok55 is described under a separate entry. Two
locomotives of this type have survived until today. Ok22-23 (Fablok
339/1929, pre-war Ok22-44, then DRG
38 4530), withdrawn from service in 1979, can be seen at the Industry and
Railway Museum in Jaworzyna Śląska. Ok22-31 (Fablok 356/1929,
pre-war Ok22-51, then DRG 38 4536),
based in Wolsztyn, was restored in service in 1987. Withdrawn in September
1997 and kept in Wolsztyn on static display, it was then overhauled (from
December 2002 to May 2004), restored in service once again and from time to time
hauls special trains. Although
only marginally superior to its archetype P8, Ok22 was a successful machine,
tough and reliable, very important for passenger traffic both before and
after WWII. Intended to supplement rather than to replace Ok1, it served
along with the older class; in fact, the last Ok1 was withdrawn a few months
later than the last Ok22. Main technical data
1)
Some sources erroneously give 540 mm 2)
Some sources give 8 560 kG 3) Ok22-1 to Ok22-5 4)
With
22D2 tender References and acknowledgments
Comprehensive
account of this class history and design by Michał ‘Doctor’ Pawełczyk can be
found at www.parowozy.best.net.
Historical and technical account can also be found in PNPP. For concise
description, see AP. Many interesting details on Wolsztyn-based locos
can be found at www.parowozy.com.pl
– this site is maintained by Wojtek Lis. |
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