Ok2

DR 38 205, photographed in Glaugau on June 16, 1990; photo by Frank Engel (www.frank-engel.de) – thanks for permission!

DR class 38^2-3 side drawing, © Lokomotiv-Revue (TB vol.1).

After WWI, newly created Polish State Railways PKP had a number of ‘exotic’ locomotive classes, sometimes represented by just a few or even single examples. The same situation, albeit to a lesser extent, occurred after WWII. Most of these locomotives were quickly withdrawn and soon fell into oblivion. Several have been preserved, but this can be attributed to peculiar twists of fate rather than deliberate action. The majority disappeared completely. One of such ephemeral classes is Ok2.

In 1910, State Railways of Saxony (Sächsische Staatsbahnen, or SäStB) received first class XII H2 locomotives for heavy passenger traffic. In comparison with earlier classes developed for similar duties, they had smaller drivers (1590 mm in diameter) and higher boiler pressure (13 bar), but shared the common feature of Belpaire-type firebox. They were designed for high tractive effort rather than speed. In fact, their maximum speed was set at 80 km/h, compared to 100 km/h of earlier classes XII H, XII HV and XII H1, but 90 km/h was often attained in service.

These locomotives were delivered between 1910 and 1922 by AG Sächsische Maschinenfabrik vorm. Richard Hartmann of Chemnitz, in several small batches, numbering 159 examples in all. During the production run, some minor modifications were introduced. First 47 examples were given SäStB service numbers 651 through 697, all assigned for the second time after various old engines withdrawn earlier. They were later re-numbered 3651 through 3697. Next 112 engines were numbered 3698 through 3809. Commonly nicknamed ‘Rollwagen’ (which roughly translates as ‘trolley’), they were considered very successful locomotives, robust and reliable, and often hauled even express trains. Initially they ran with SäStB 2’2’T16 tenders, later larger 2’2’T21 was standardized. Class XII H2 has sometimes been compared to the renowned Prussian P8 (Ok1 in the PKP service), but in fact all that these engines shared was the axle arrangement: Saxon locomotive, with 1590 mm drivers compared to 1750 mm of P8, was slower, but yielded higher tractive effort, and thus proved particularly useful in mountain areas.

According to the Lokomotiv-Archiv Sachsen 1 (see references), six engines were lost during the war. Class XII H2 was considered valuable war booty, so 25 went to France (ETAT 230-960 through 984, later SNCF 3-230-E-960 through 984) and four to Belgium (SNCB class 63). The rest were later absorbed by DRG and classed 38^2-3 (service numbers 38 201 through 324). In 1927, DRG ordered an additional batch of ten engines, with various minor modifications (numbered 38 325 through 334), bringing total output to 169 examples. Furthermore, in 1940, after the fall of France, DRG took over five ex-SNCF engines (38 204, second with this number, and 38 351 through 354). After WWII, most engines of this type were taken over by DR in Eastern Germany, which finally ended up with 75 examples; last were withdrawn in 1972, although three probably enjoyed longer service life with industrial establishments. DB had only one, scrapped in 1955. In 1938, after the annexation of Bohemia and Moravia, most of these engines were transferred to Sudetenland, where they proved particularly useful. ČSD thus took over 61 examples, but at least nine were transferred to DR, PKP and MPS (Soviet ministry of transport – only one, most probably for tests). They were classed 365.5, but only ten were given service numbers 365.5500 through 5509. The rest probably saw little service and most were scrapped in late 1940s or early 1950s. Last two in service, 365.5505 and 365.5507, survived until 1959.

Polish railways acquired just five examples, classed Ok2; of these, two were transferred from ČSD and one from DR. Little is known about their service; in fact, Ok2 is one of the most obscure post-war PKP locomotive classes and many references even don’t mention it at all. Most probably all five Ok2s served in southern Poland. Their life was very short: two were written off as early as in 1950 and the last one, Ok2-3 (Hartmann 3390/1910, formerly SäStB 659, renumbered 3659, then DRG 38 208), ironically the oldest of all five, survived until 1953. Of course, all were scrapped. It is somehow surprising that these successful, robust and useful engines were outlived, not only in Poland, by many obsolete ones: many were written off after less than thirty years in service, which indeed is not very much for a good steam locomotive. Only one has been preserved: DR 38 205 (Hartmann 3387/1910, SäStB 656, renumbered 3656), withdrawn in 1971, was transferred to the Verkehrsmuseum Dresden and probably remained operational for quite a long time, at least judging from several known photos. Currently it is on static display at Sächsisches Eisenbahnmuseum in Chemnitz, its birthplace. Information on Polish Ok2s is very scarce, but – quite surprisingly – the H0-scale model of Ok2-4 (Hartmann 3919/1916) is to be released by Piko in 2008.

Main technical data

No.	Parameter	Unit	Value
1.	Years of manufacture	-	1910 – 1927
2.	Total built / used in Poland	-	169 / 5
3.	Tender class	-	22D2 (?)
4.	Axle arrangement	-	2-3-0
5.	Design maximum speed	km/h	80
6.	Cylinder bore	mm	2 X 550
7.	Piston stroke	mm	630
8.	Engine rating	kW/hp	890 / 1 210
9.	Tractive effort	kG
10.	Boiler pressure	MPa	1.33
11.	Grate dimensions	m X m	2.83 m^2
12.	Firebox heating surface	m^2	13.44
13.	Distance between tube plates	mm	4 200
14.	Number of flue tubes	-	180
15.	Heating surface of flue tubes	m^2	109.26
16.	Number of smoke tubes	-	24
17.	Heating surface of smoke tubes	m^2	36.87
18.	Evaporating surface, total	m^2	159.57
19.	Superheater heating surface	m^2	43.2
20.	Diameter of drivers	mm	1590
21.	Diameter of idlers front/rear	mm	1065 / -
22.	Total weight, empty	kg	65 600
23.	Total weight, working order	kg	73 300
24.	Weight on drivers, working order	kg	47 100
25.	Weight with tender, empty	kg
26.	Weight with tender, working order	kg
27.	Maximum axle load	T	15.7
28.	Axle base (with tender)	mm	15 536^1)
29.	Overall length (with tender)	mm	18 971^1)
30.	Brake type	-	Westinghouse

1) With 2’2’T21 tender.

References and acknowledgments

Basic technical and historical data have been taken from TB vol.1, EZ vol.2 and Lokomotiv-Archiv Sachsen 1 by F.Näbrich, G.Meyer and R.Preuß (Transpress, 1984). Statistical data, as usually, have been taken mostly from Ingo Hütter’s database (www.lokomotive.de). I would like to thank Frank Engel for information on 38 205.