Ol12-7, the sole surviving example in Poland, photographed at the Chabówka heritage park in June 2001.




The same machine, photographed on April 13, 2004.




Ol12-4. My data give ‘location unknown, June 1959’, but this may be a pre-war picture. Photo from my collection.




Ol12-7 inside the Chabówka shed; November 12, 2008. In September 2009 this engine participated in the ‘Parowozjada 2009’ steam gala: some pictures can be seen here.

And in September 2013 this engine visited Warsaw – some pictures are there.




KkStB 429.117 (BMMF 402/1911) later became ČSD 354.737 and survived in service until January 1964. Postcard from my collection.



Ol12-7 visited Warsaw again on October 26, 2014; this picture was taken near Warszawa Miedzeszyn station, a few minutes’ walk from where I live.



An earlier visit of the Ol12-7 in Warsaw: June 17, 1995. Photo by Marek Niemiec (from my collection).



Another picture of the Ol12-7 by the same author: Sucha Beskidzka, June 7, 1996.



Side drawing of class 429; source: Triebfahrzeuge österreichischer Eisenbahnen: Dampflokomotiven BBÖ und ÖBB (see References).

Between 1907 and 1909, Austrian (kkStB) and Hungarian (MÁV) state railways took delivery of 148 passenger locomotives with  the 1-3-1 axle arrangement (93 and 65 examples, respectively), built by four manufacturers (WLF, Wiener Neustadt, StEG and BMMF). Two more went to k.u.k. Heeresbahn Banjaluka-Doberlin in Bosnia. After WWI, 21 kkStB engines were taken over by PKP and classed Ol11. These locomotives were fitted with compound engines and ran on saturated steam. Initially Austro-Hungarian railways did not favor superheated steam, as they were afraid that high-grade lubricants, necessary with higher steam temperature, could be in short supply. For this reason, Austrian manufacturers produced a considerable number of compounds and Gölsdorf preferred this layout. Advantages of steam superheating, however, finally prevailed and some of these engines were later redesigned and fitted with superheaters. Class 329 was no exception and was developed into class 429, which featured steam superheating. Prototype (StEG 3581/1909) was followed by 56 examples which retained almost identical steam engines and externally hardly differed from class 329. Further 132 engines (class 429.100) differed mainly in having piston valves on both cylinders (initially low-pressure cylinder had a slide valve). Tractive effort and maximum speed remained unchanged. Compounds remained in production until 1912; furthermore, in 1916, StEG built an additional batch of ten examples (s/n 4078 through 4087, KkStB 429.216 through 225, included in the above total). Almost all went to KkStB. Only six (built by Magyar Királyi államvasutak gépgyára, Budapest) served with Südbahn, but due to certain differences they are sometimes considered a separate class.

In parallel, a single-expansion version was developed and accepted as class 429.900. Prototype (WLF s/n 2018) was accepted in 1911 and production started in 1913, to last until the end of the war. Superheater was slightly enlarged and boiler pressure reduced from 15 to 14 bar. Tractive effort and power increased by a few percent. 197 engines were delivered, all to KkStB, bringing the total up to 386 examples from StEG (135), WLF (159), Wiener Neustadt (49), BMMF (37) and Magyar Királyi államvasutak gépgyára (6).

After the war, these locomotives were divided between several countries. 86 examples remained with Austrian railways BBÖ, 152 went to Czechoslovakia (ČSD class 354.7) and 25 to Italy (FS class 688). Small numbers served in Romania, Yugoslavia and Hungary. In 1926, ČSD launched a reconstruction program, with the aim of unification within the 354.7 class made up of three distinct versions. All machines were fitted with single-expansion engines and boilers with two steam domes, connected with a horizontal tube. Only two compounds survived until 1938. Some ČSD machines were also fitted with Westinghouse brakes and modified smoke-box door. Last of them were withdrawn in 1970. With ÖBB and FS these engines survived until mid-1960s.

PKP after WWI acquired 106 engines in all three versions (18, 28 and 60, respectively). Some sources give 18, 27 and 61, respectively. This error results from the fact that Ol12-84 (ex 429.216) was from the above-mentioned batch of ten compounds, built by StEG in 1916. All were classed Ol12 and numbered Ol12-1 through 18 (ex 429), Ol12-19 through 45 (ex 429.100) and Ol12-46 through 106 (ex 429.900, with the exception of Ol12-84). Due to comparatively low axle load, they were particularly suitable in areas where weak tracks dominated, so they served almost exclusively in southern and south-eastern Poland. In 1939, forty fell into German hands and were impressed into DRG class 352,3, which included Austrian and Czechoslovakian engines taken over in 1938 (service numbers 35 349 through 388). One (Ol12-24, ex 429.116, BMMF 401/1911) went to Hungary, possibly with an evacuation train, later served with MÁV as 323,907, then went to industry and was not returned. All remaining 65 Ol12s were captured by the Soviets and later served with Polish numbers, written in Russian script. Fifty of them later became German war booty and were given DRG numbers 35 392 through 400 (after ex-Yugoslavian engines captured in 1941) and 35 801 through 829, but many of these numbers were assigned only formally and the engines actually ran with old Polish designations. Some served with Ostbahn (similarly, with original Polish numbers), while two (Ol12-25, ex 429.121, BMF 406/1911, and Ol12-65, ex 429.972, WLF 2282/1916) were handed over directly to Romanian state railways CFR – the latter was re-numbered 131.901.

After WWII, only a handful of engines were returned directly. As most ex-Austrian locomotives were directed by DRG to Austria or Czechoslovakia, the majority of pre-war Ol12s went to ÖBB or ČSD. Most of them were later identified as Polish property and returned in late 1940s. Eight engines taken over by Yugoslavian railways JDŽ were returned in 1949. Two ex-Austrian engines that did not serve with PKP before the war were also taken over: 429.175, then DRG 35 333, and 429.159, then DRG 35 327, became Ol12-1 and Ol12-3, respectively. Finally, in 1955, eight locomotives were returned by DR, in a very poor condition, only to be scrapped without even being given service numbers. In all, PKP received 57 examples, of which 47 were restored in service. Apart from their traditional assignment to southern Poland, some later served in north-eastern region. A few were converted to oil firing and used on the Puck-Hel area on the Baltic coast, where fire hazard in forest areas excluded coal firing. Most were withdrawn in late 1950s or early 1960s; probably the last one was Ol12-43. This engine (WLF 2280/1916) had an eventful life. After a brief service with KkStB as 429.970 it was taken over by BBÖ, but in 1924 went to PKP and was designated Ol12-64. In 1939 it was captured by the Soviets and later fell into German hands, to become 35 399. After the war it served briefly with JDŽ as 106-017; in 1949 was returned to PKP and remained in service until March 1966.

Ol12-7 is the only engine of this type preserved in Poland. Most sources give that this locomotive is StEG 3849/1912, ex KkStB 429.195, which served with PKP before the war as Ol12-43. In 1939 it was captured by the Soviets, then served with DRG as 35 817, after the war went to Austria, but in April 1947 returned to Poland. The problem is that Ol12-7 has a single-expansion steam engine! Either it was rebuilt after WWII (possibly fitted with boiler and steam engine taken for another machine), or Ol12-7 plates were fitted to a former 429.900 – such operations were not uncommon. I have found no information that would support either of these conjectures. Anyway, Ol12-7 is alive and quite well. In 1993 it was restored to the working order and for a few years was the oldest operational steam engine in Poland. After boiler ticket expiry in 1999, this engine was overhauled and restored in service in 2008. Two more examples have survived until today, namely ÖBB 35.233 (ex KkStB 429.1971, StEG 4147/1916) in Austria and ČSD 534.7152 (ex KkStB 429.1996, BMMF 657/1917) in the Czech Republic.



Main technical data







Years of manufacture


1909 – 1918


Total built / used in Poland


197 / 61

(183 / 45)1)


Tender class




Axle arrangement




Design maximum speed




Cylinder bore


2 X 475

(475 / 690)


Piston stroke




Engine rating


925 / 1 260

(830 / 1 130)


Tractive effort


8 600 (8 100)


Boiler pressure


1.43 (1.53)


Grate dimensions

m X m

2.88 X 1.06


Firebox heating surface




Distance between tube plates


4 060


Number of flue tubes




Heating surface of flue tubes




Number of smoke tubes




Heating surface of smoke tubes




Evaporating surface, total




Superheater heating surface




Diameter of drivers


1 575


Diameter of idlers front/rear


830 / 830


Total weight, empty


55 800


Total weight, working order


61 200


Adhesive weight, working order


43 000


Weight with tender, empty


72 800


Weight with tender, working order


100 200


Maximum axle load




Axle base (with tender)


13 845


Overall length (with tender)


16 945


Brake type


vacuum, Westinghouse


-       Data in brackets for compound engine version.


References and acknowledgments


-       EZ, LP, AP;

-       www.pospichal.net/lokstatistik (website by Josef Pospichal);

-       Tomisław Czarnecki, Dieter Zoubek and Ingo Hütter (private communication);

-       Triebfahrzeuge österreichischer Eisenbahnen: Dampflokomotiven BBÖ und ÖBB by Heribert Schröpfer (Alba, 2002).