OKl101

DRG 75 501 (Hartmann 3836/1915), photographed at Neuenmarkt on July 30, 1996.

Side drawing of class 75⁵ from TB vol.2.

75 515 (Hartmann 3477/1911), photographed in Chemnitz-Hilbersdorf on August 23, 2006 by someone who wishes to be known as Wassen. Source: www.commons.wikimedia.org.

DR 75 501 again, this time in normal service, photographed in Löbau in 1973 by P. Klimpel. Photo from my collection.

DR 75 521 (ex SäSt 1815, Hartmann 3585/1912), location unknown, 1966. This engine was withdrawn in December 1968. Photo from my collection.

SäSt 1870 (Hartmann 3939/1917), location and date unknown – probably a factory photo. This engine later became DRG 75 563; taken over by DR, it was written off in June 1969. Photo from my collection.

Yet another picture of DR 75 501, taken in Chemnitz-Hilbersdorf on May 7, 2005 by someone who wants to be known as Geme (source: www.commons.wikimedia.org).

In 1911, state railways of Saxony Königlich Sächsische Staatseisenbahnen (SäSt) introduced class XIV HT passenger tank locomotive, intended mainly for suburban service. Until 1917, 95 examples were built by Sächsische Maschinenfabrik vorm. Richard Hartmann AG of Chemnitz; further eleven followed in 1921, bringing the grand total to 106. XIV HT was a modern machine with moderate axle load of 16.5 tonnes, running on superheated steam and fitted with Belpaire firebox. Front and rear Adams idle axles were perhaps not an ideal solution for a passenger machine with drivers almost 1600 mm in diameter, but they were considered satisfactory for design maximum speed of only 75 km/h.

Prototype (s/n 3472/1911) and next seven examples were initially given service numbers 1343 through 1350, but later they were renumbered and the entire batch was given numbers from 1801 to 1906 inclusive. Several modifications were introduced during production, so that four distinct variants can be distinguished. Later versions (from No.1816, s/n 3617/1912 onwards) can be easily identified by sloping upper front water box panels. Last 51 examples (from No.1856, s/n 3925/1917 onwards) had enlarged coal and water boxes; coal capacity increased from 2.5 to 2.8 tonnes and water capacity – from 8 to 9 cu.m. These machines had their conical, pointed smoke-box doors replaced by more typical slightly convex ones.

After WWI, four machines went to Belgium (NMBS/SNCB class 96) and eight to France (ETAT class 32), as a part of war reparations. 83 engines remained in Germany and were impressed into DRG as class 75⁵. Polish railways received eleven examples, classed OKl101. Together with other passenger tank engines of various types, they were used mainly with suburban trains; their basic characteristics were similar to that of indigenous OKl27, designed for the same duties (in fact, it had initially been planned to base the OKl27 design on the Saxon engine!). All of these comparatively modern and useful machines survived in service until 1939. OKl101-3 (ex SäSt 1811, 3581/1912) was taken over by the Germans and re-numbered 75 706. At least eight examples fell into Soviet hands. Of these, seven became German war booty after Fall Barbarossa. Four of them (OKl101-2, -6, -7 and -11) were re-numbered 75 707 through 710 between 1941 and 1942. OKl101-1 (ex SäSt 1802, 3473/1911) went to Ostbahn and retained its original PKP service number. OKl101-4 (ex SäSt 1813, 3583/1912) and OKl101-5 (ex SäSt 1822, 3623/1912) were re-numbered 75 589 and 75 590, respectively, only in 1945. The fate of OKl101-8 (ex SäSt 1842, 3827/1915) after 1939 is not known; this engine was returned by French SNCF and re-numbered OKl101-1. On OKl101-10 (ex SäSt 1864, 3933/1917) I have no reliable information. The highest DRG number, 75 591, was assigned to ex-SäSt 1868 (3937/1917, later ETAT 32-916), captured in France.

Most engines of this type after WWII remained in Eastern Germany: 89 examples went to DR. Most of them were withdrawn in late 1960s. The last one, 75 515 (ex SäSt 1806, 3477/1911) survived in service until September 1971. At least four later went to industry. DB did not use these locomotives. According to most sources, Poland regained just three machines, but only the above-mentioned OKl101-1 was re-numbered and saw some service. OKl101-1 and OKl101-4 were returned by DR in 1956 and scrapped. According to EZ, three locomotives served with ČSD as class 355.1; however, www.beitraege.lokomotive.de lists only two. DRG 75 545 (ex SäSt 1844, 3829/1915) became 355.1500 and was withdrawn in 1950. Ex-PKP OKl101-6 (ex SäSt 1839, DRG 75 509, 3640/1913) was impressed as 355.1501 and survived in service until 1949. Two examples have survived until today, both in Germany. 75 515, the last one in DR service, after withdrawal went to Verkehrsmuseum Dresden and later was plinthed in Karl-Marx-Stadt (now Chemnitz), its birthplace. This machine is now preserved at Verein Sächsisches Eisenbahnmuseum (SEM) in Chemnitz-Hilbersdorf. 75 501 (ex SäSt 1851, 3836/1915), withdrawn in 1967, was transferred to Deutsche Dampflokmuseum, Neuenmarkt/Oberfranken, in December 1977 and restored to operational status.

Main technical data

No.	Parameter	Unit	Value
1.	Years of manufacture	-	1911 – 1921
2.	Total built / used in Poland	-	106 / 11
3.	Tender class	-	-
4.	Axle arrangement	-	1-3-1
5.	Design maximum speed	km/h	75
6.	Cylinder bore	mm	2 x 550
7.	Piston stroke	mm	600
8.	Engine rating	kW/hp	728 / 990
9.	Tractive effort	kG
10.	Boiler pressure	MPa	1.22
11.	Grate dimensions	m x m	2.30 m^2
12.	Firebox heating surface	m^2	11.8
13.	Distance between tube plates	mm	4 000
14.	Number of flue tubes	-	132
15.	Heating surface of flue tubes	m^2
16.	Number of smoke tubes	-	24
17.	Heating surface of smoke tubes	m^2
18.	Evaporating surface, total	m^2	123.92
19.	Superheater heating surface	m^2	35.86
20.	Diameter of drivers	mm	1 590
21.	Diameter of idlers front/rear	mm	1 065 / 1 065
22.	Total weight, empty	kg	64 200^1)
23.	Total weight, working order	kg	82 200^1)
24.	Weight on drivers, working order	kg	49 500^1)
25.	Weight with tender, empty	kg	-
26.	Weight with tender, working order	kg	-
27.	Maximum axle load	T	16.5
28.	Axle base (with tender)	mm	8 700
29.	Overall length (with tender)	mm	12 415
30.	Brake type	-	Westinghouse

1) Refers to later version (from No. 1856 onwards).

List of vehicles can be found here.

References and acknowledgments

- Lokomotiv-Archiv Sachsen 2 by F. Näbrich, G. Meyer and R. Preuss (Transpress, Berlin, 1984);

- TB vol.2;

- Ingo Hütter’s locomotive database (available at www.beitraege.lokomotive.de).