Ol12

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.

Between 1907 and 1910, three Austrian manufacturers (Wiener Neustadt, StEG and BMMF) produced 150 passenger engines with the 1-3-1 axle arrangement, designed by renowned Karl Gölsdorf. They went to KkStB (93, class 329) MÁV (65, class 323) and Austro-Hungarian military railways KkHB (two, class 6). After WWI, 21 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 35^2,3, which included Austrian and Czechoslovakian engines taken over in 1938 (service numbers 35 349 through 388). As far as I know, one (Ol12-24, ex 429.116, BMMF 401/1911) went to Hungary, possibly with an evacuation train, later served with MÁV as 323.907 and was not returned. Most probably all remaining Ol12s were captured by the Soviets and later served with Polish numbers, written in Russian script. Many 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.

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, 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. Currently it is under repair and will probably be restored in service. 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

No.	Parameter	Unit	Value
1.	Years of manufacture	-	1909 – 1918
2.	Total built / used in Poland	-	197 / 61 (183 / 45)¹⁾
3.	Tender class	-	16C11
4.	Axle arrangement	-	1-3-1
5.	Design maximum speed	km/h	80
6.	Cylinder bore	mm	2 X 475 (475 / 690)
7.	Piston stroke	mm	720
8.	Engine rating	kW/hp	925 / 1 260 (830 / 1 130)
9.	Tractive effort	kG	8 600 (8 100)
10.	Boiler pressure	MPa	1.43 (1.53)
11.	Grate dimensions	m X m	2.88 X 1.06
12.	Firebox heating surface	m²	14.2
13.	Distance between tube plates	mm	4 060
14.	Number of flue tubes	-	136
15.	Heating surface of flue tubes	m²	79.56
16.	Number of smoke tubes	-	18
17.	Heating surface of smoke tubes	m²	25.8
18.	Evaporating surface, total	m²	119.56
19.	Superheater heating surface	m²	23.8
20.	Diameter of drivers	mm	1 575
21.	Diameter of idlers front/rear	mm	830 / 830
22.	Total weight, empty	kg	55 800
23.	Total weight, working order	kg	61 200
24.	Adhesive weight, working order	kg	43 000
25.	Weight with tender, empty	kg	72 800
26.	Weight with tender, working order	kg	100 200
27.	Maximum axle load	T	14.4
28.	Axle base (with tender)	mm	13 845
29.	Overall length (with tender)	mm	16 945
30.	Brake type	-	vacuum, Westinghouse

1) Data in brackets for compound engine version.

References and acknowledgments

Comprehensive historical and technical account can be found in EZ. Concise information can be found in AP. Information on individual examples has been taken from the Josef Pospichal’s website www.pospichal.net. Many thanks to Ingo Hütter, Dieter Zoubek and Tomisław Czarnecki for information on the Ol12-7.