DR series 99.23–24

Class 99.23-24
99 7236
Numbering:	99 231-247 from 1970: 99 7231-7247
Number:	17th
Manufacturer:	LKM Babelsberg
Year of construction (s):	1954-1956
Type :	1'E1 'h2t
Genre :	K 57.10
Gauge :	1000 mm ( meter gauge )
Length over buffers:	12,500 mm
Height:	03,650 mm
Width:	02,645 mm
Fixed wheelbase:	4800 mm
Total wheelbase:	8700 mm
Empty mass:	47.5 t
Service mass:	60.5 t
Friction mass:	47.5 t
Wheel set mass :	9.5 t
Top speed:	40 km / h
Indexed performance :	515 kW (700 hp)
Starting tractive effort:	103 kN
Driving wheel diameter:	1000 mm
Impeller diameter:	0550 mm
Control type :	Heusinger with a Kuhn loop
Number of cylinders:	2
Cylinder diameter:	500 mm
Piston stroke:	500 mm
Boiler overpressure:	14 bar
Number of heating pipes:	114
Number of smoke tubes:	032
Grate area:	02.8 m²
Radiant heating surface:	10.4 m²
Superheater area :	30 m²
Evaporation heating surface:	95.5 m²
Water supply:	8 m³
Fuel supply:	4 tons of coal
Brake:	K-GP mZ
Locomotive brake:	Suction-controlled compressed air brake type Hardy with additional brake type Knorr, converted to a single-release compressed air brake with control valve KNORR EMV10 and additional brake. All coupled wheel sets braked from the front on one side
Train brake:	Hardy type suction air brake, converted to Knorr type air brake
Coupling type:	Balancing lever coupling , in Eisfeld central buffer coupling type Janney

The vehicles of the 99.23 series are meter-gauge steam locomotives ( new construction locomotives ) procured by the Deutsche Reichsbahn . When they were classified in the company park, they were given the company numbers 99 231 to 99 247.

history

Between 1954 and 1956, the Deutsche Reichsbahn procured a total of 17 new locomotives to replace the partly outdated and, moreover, heterogeneous locomotive stock of the Harzquer and Brocken Railway and the narrow-gauge railway Eisfeld – Schönbrunn . The initially planned use of 99 233 and 99 234 on the Gera-Pforten – Wuitz-Mumsdorf railway line was quickly discarded because the superstructure was too light.

Locomotive 99 7231 with a trolley freight train in the Stiege station (1990)

The Harzquerbahn initially received 13 machines. After the closure of the narrow-gauge railway Eisfeld-Schönbrunn the four new steam locomotives used there (99 231, 99235-237) came to Lokeinsatzstelle Wernigerode . However, the clutch and brake had to be adapted to the Harz railways by autumn 1974, and as described below, the chassis was adapted to that of the second delivery series by installing Eckhardt bogies with Beugniot levers .

Due to the large number of new locomotives then available in Wernigerode, these were also used as planned on the Selketalbahn at times . On the Selketalbahn, they relieved the old Mallet locomotives 99.590 / 99 5906 that were moved there from the Harzquer and Brocken Railway .

The eleven operational locomotives are now mainly used on the Harzquerbahn and in Brocken traffic from Wernigerode and Nordhausen Nord. Their company numbers changed from 99 231 ff. With the introduction of the computer numbers in 1970 to 99 7231 ff. And after the installation of the oil firing to 99 0231 ff. The HSB continues to use the Deutsche Reichsbahn series scheme from 1970.

Technical details

The design was derived from the standard locomotives of the DR class 99.22 and takes over their essential dimensions. The new locomotives are, however, made entirely of welded construction; instead of the bar frame of the standard locomotives, they have a welded sheet metal frame , a more elaborate running gear construction and fully welded boilers with mixing preheaters.

The first seven copies (99 231 to 99 237) were originally equipped with two Krauss-Helmholtz steering racks , each formed from the wheel set at the respective end of the locomotive and the adjacent coupling wheel set . However, due to the tight curve radii of the Harz routes, there were considerable problems with the sheet travel, which initially prevented the route from being used. For this reason, three-axle Schwartzkopff-Eckhardt steering racks were formed from the front wheel set and the first and second coupled wheel sets for the machines in the second batch . The locomotives of the first series were converted accordingly between 1959 and 1961 and 1973/74 (the Eisfeld locomotives, the last being 99 7231).

Detail of a technical drawing of the steam locomotive number 99 7242-3 of the Deutsche Reichsbahn

The initially weakened wheel flanges of the drive wheel sets were later completely dispensed with in favor of better arc travel, but they were equipped with wider bandages. Since only the third, i.e. the driving wheel set, and the fourth coupled wheel set are firmly mounted in the locomotive frame, but a wheel set without flange can not take on any cornering work, the locomotives no longer have a fixed wheelbase, but only a so-called guided length, which was already provided by Richard was theoretically considered appropriate by Helmholtz , the developer of the Krauss-Helmholtz frame.

The two-cylinder superheated steam engine with simple steam expansion drives the third coupled wheel set as a drive wheel set; the locomotives have Heusinger control with a Kuhn loop and initially springless pressure compensation piston valves of the Müller type , later converted to Trofimoff valves .

The sheet metal frame of the new locomotives, which was used instead of the bar frame of the standard locomotives, was not as robust as the former, cracks and bends appeared from the beginning, which led to difficulties in maintenance. From 2004 to 2010 ten locomotives (7232, 7234, 7236, 7237, 7239, 7240, 7241, 7243, 7245, 7247) were equipped with a new, structurally revised sheet metal frame and new steam cylinders in welded construction (the 99 7241 received the new cylinders as early as 2001). 99 7235 is the only still operational locomotive with the original frame at the end of 2016. All other locomotives are still present in the resin, but no longer operational, and mostly in smaller engine shed at ranges provided z .

All machines were equipped with main oil firing between 1976 and 1981 , but because of the energy crisis in the GDR, they were converted back to coal firing in 1982–1984. They are the most powerful narrow-gauge steam locomotives that have been used on German routes to date. With an overall efficiency of around 5.5%, they are also among the most economical narrow-gauge locomotives used in Germany. During test drives it was found that the calculated heating surface load of the boiler without a combustion chamber, determined as the boiler limit, could be increased from 55 kg / m²h to 68 kg / m²h without problems. In order not to damage the boiler and engine in the long term through excessive loads, the performance tables were based on a heating surface load of 60 kg / m²h; At this boiler limit, the maximum effective power on the towing hook was 585 PSe at a speed of 15 km / h.

Vehicle list

Company number	Operating condition	Place of use / Storage location	Remarks	image
99 7231	z-posed	Ilfeld	shut down since 2001
99 7232	operational	Wernigerode	2004 new frame
99 7233	z-posed	Ilfeld	shut down since 2000
99 7234	operational	Wernigerode	2009 new frame
99 7235	operational	Wernigerode	(old frame)
99 7236	operational	Wernigerode	2008 new frame
99 7237	operational	Wernigerode	2011 new frame
99 7238	z-posed	Wernigerode western gate	shut down since 2013
99 7239	operational	Wernigerode	2007 new frame
99 7240	operational	Gernrode	2005 new frame
99 7241	operational	Wernigerode	2009 new frame
99 7242	z-posed	Benneckenstein	shut down since 2009
99 7243	operational	Wernigerode	2010 new frame
99 7244	z-posed	Hasselfelde	shut down since 1999
99 7245	Repair and boiler inspection	Wernigerode western gate	2006 new frame
99 7246	z-posed	Benneckenstein	shut down since 1996
99 7247	operational	Wernigerode	2012 new frame

• 

  New steam locomotives in Wernigerode

• 

  New steam locomotive in Alexisbad

• 

  Rear view 99 7245 in Eisfelder Talmühle

• 

  Side view 99 7243 in Quedlinburg

• 

  99 236 (2017)

• 

  99 232 Exit Drei Annen Hohne

literature

• Manfred Weisbrod, Hans Wiegard, Hans Müller, Wolfgang Petznick: German Locomotive Archive: Steam Locomotives 4 (Class 99) . transpress, Berlin 1995, ISBN 3-344-70903-8 , pp. 53-57 .
• Klaus J. Vetter: The great manual of German locomotives . Bruckmann, Munich 2001, ISBN 3-7654-3764-6 , pp. 191-192 .
• Horst J. Obermayer: Paperback German narrow-gauge steam locomotives . Franckh'sche Verlagshandlung, Stuttgart 1971, ISBN 3-440-03818-1 , p. 60-61 .
• Dirk Endisch: Harz giants class 99.23 . Verlag Ingrid Zeunert, Gifhorn 2003, ISBN 3-924335-34-6 , p. 2-126 .

Web links

Commons : DR Series 99.23–24  - Collection of pictures, videos and audio files

• Website of the Friends of the Selketalbahn
• HSB website

Individual evidence

1. ↑ EK Topics 18, Brockenlok 99.22 , Eisenbahn-Kurier, Freiburg 1995
2. ^ Obermayer: Paperback German narrow-gauge steam locomotives. Franckh'sche Verlagshandlung, Stuttgart 1971, ISBN 3-440-03818-1
3. ↑ Kühne: Everything about GDR steam locomotives , transpress, Stuttgart 2008, ISBN 978-3-613-71335-2
4. ↑ Website of the Friends of the Selketalbahn (see web links)
5. ↑ Michael U. Kratzsch-leichsenring, Dirk Endisch: Big chunks not just for the chunk . In: railway magazine . No. 2 , 2017, ISSN  0342-1902 , p. 24 .