Th24

Photographs of Polish Th24 are very few and poor. Fortunately, I obtained three excellent photos of KkStB machines from Josef Pospichal – many thanks! This one is 59.05...

... this one – 59.177...

...and this – 59.140. The latter machine (WLF 1331/1900) later served with DRG as 53 7203 and in 1945 became Th24-2.

Between 1888 and 1900 three Austrian locomotive manufacturers (Wiener Neustadt, WLF and StEG) built 153 freight locomotives with 0-3-0 axle arrangement, designated class 56. Most of them (132) went to the KkStB (Kaiserlich-königliche österreichische Staatsbahnen), the rest served with various private railway companies. They were quite simple, single-expansion machines, running on saturated steam. Soon after their appearance Karl Gölsdorf proposed a variant with compound engine. Gölsdorf was one of the keenest advocates of such layout, due to better economy, despite more complex design and certain maintenance problems. New machine appeared in 1893 and was soon accepted by KkStB as class 59. Until 1903, 193 examples were built by Wiener Neustadt, WLF, Krauss Linz, StEG and BMF (later known as PČM). 59.100 was written off before 1918, so some sources erroneously give 192 as the total output.

Apart from the steam engine, class 59 did not differ much from its predecessor and featured inner frame, 1258-mm drivers and one large steam dome. Some examples were fitted with large, Rihosek-type spark arrester, typical for many Austrian locomotives. Instead of two cylinders 450 mm in diameter, there was a high-pressure left cylinder (500 mm) and low-pressure right one (740 mm); Heusinger valve gear, then a novelty in Austria, replaced earlier Gooch mechanism. Tractive effort was marginally lower than in class 56, but coal consumption was reduced by 20 to 25 percent.

As with other Austro-Hungarian classes, after 1918 these locomotives were distributed among several countries. Of 39 examples in Czechoslovakia in 1918, 30 served with ČSD as class 324.2; withdrawals started well before WWII and last were written off in 1949. 26 examples were impressed into CFR service in Romania – I have no information on their subsequent service. Yugoslavian railways JDŽ received sixteen, classed 121; later they were re-classed 127, but only few (five?) served briefly after WWII.

Polish railways obtained 80 machines, classed Th24. As with class Th20 (ex-Austrian 56), this designation did not comply with the system in use with PKP, wherein engines of Austrian origin were allocated numerical designations from 11 to 19. The reason is that there were comparatively many types and sub-types of Austrian three-axle freighters (some represented only by few or even single examples, but each being allocated a distinct designation), so numbers simply ran out. Many of them had served on local lines in Galicia, which became a part of Poland in 1918. Even by 1920s standards, Th24 was not a particularly advanced design; furthermore, compounds were not favored by PKP. It is no wonder, thus, that this class, initially quite numerous among ‘Austrians’, rapidly fell in number. Almost half Th24s were withdrawn before 1931 and only 15 (some sources give 14) remained in PKP rosters until September 1939. Of these, twelve were taken over by the Germans and impressed into Ostbahn service as class 53⁷². Three were captured by the Soviets and probably remained in Ukraine, to fall into German hands later (in all, German railways had 19 examples). After WWII, eleven ex-Polish machines returned, plus an ex-Austrian one (DRG 53 7203, ex 59.140, WLF 1331/1900). Only eight of these elderly and totally obsolete engines were impressed as Th24-1 through TKh24-8 and saw some post-war service; four, returned by DR or JDŽ between 1949 and 1955, were not given PKP numbers and were probably scrapped or cannibalized. As in other countries, last were withdrawn in the 1950s. No example of this class is known to have survived until today.

Main technical data

No.	Parameter	Unit	Value
1.	Years of manufacture	-	1893 – 1903
2.	Total built / used in Poland	-	193^1) / 80
3.	Tender class	-	12C11^2)
4.	Axle arrangement	-	0-3-0
5.	Design maximum speed	km/h	50
6.	Cylinder bore	mm	500 / 740
7.	Piston stroke	mm	632
8.	Engine rating	kW/hp	390 / 530
9.	Tractive effort	kG	8 400
10.	Boiler pressure	MPa	1.22
11.	Grate dimensions	m X m	1.81 m^2
12.	Firebox heating surface	m^2	8.0
13.	Distance between tube plates	mm
14.	Number of flue tubes	-	166
15.	Heating surface of flue tubes	m^2	124.0
16.	Number of smoke tubes	-	-
17.	Heating surface of smoke tubes	m^2	-
18.	Evaporating surface, total	m^2	132.0
19.	Superheater heating surface	m^2	-
20.	Diameter of drivers	mm	1258
21.	Diameter of idlers front/rear	mm	- / -
22.	Total weight, empty	kg	37 500
23.	Total weight, working order	kg	42 000
24.	Weight on drivers, working order	kg	42 000
25.	Weight with tender, empty	kg	52 500^3)
26.	Weight with tender, working order	kg	74 000^3)
27.	Maximum axle load	T	14.0
28.	Axle base (with tender)	mm	10 590
29.	Overall length (with tender)	mm	15 088
30.	Brake type	-	Hardy

1) Some sources erroneously give 192 examples.

2) 11C12, 11C13 and 12C13 three-axle tenders were also used.

3) With 12C11 tender.

References and acknowledgments

Technical and historical account can be found in EZ vol.1 Information on individual examples has been taken from the impressive Ingo Hütter’s locomotive database (available at www.lokomotive.de). Photographs of Austrian 59s have come from Josef Pospichal – thanks a lot!