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DR Class 99.23-24

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DR Class 99.23–24
99 7243-1 in 2006
Type and origin
Power typeSteam
BuilderVEB Lokomotivbau "Karl Marx" Babelsberg
Serial number134008–134028
Build date1954–1956
Total produced21
Specifications
Configuration:
​
 • Whyte2-10-2T
 • UIC1′E1′ h2t
 • GermanK 57.10
Gauge1,000 mm (3 ft 3+3⁄8 in)
Leading dia.0,500 mm (1 ft 7+5⁄8 in)
Driver dia.1,000 mm (3 ft 3+3⁄8 in)
Trailing dia.0,550 mm (1 ft 9+5⁄8 in)
Wheelbase:​
 • Axle spacing
(Asymmetrical)
  • 1,950 mm (76+3⁄4 in) +
  • 1,200 mm (47+1⁄4 in) +
  • 1,200 mm (47+1⁄4 in) +
  • 1,200 mm (47+1⁄4 in) +
  • 1,200 mm (47+1⁄4 in) +
  • 1,950 mm (76+3⁄4 in) =
 • Engine8,700 mm (342+1⁄2 in)
Length:
​
 • Over couplers11,730 mm (461+3⁄4 in)
 • Over headstocks11,100 mm (437 in)
Width2,645 mm (8 ft 8+1⁄8 in)
Height3,650 mm (11 ft 11+11⁄16 in)
Axle load9.5 t (9.3 long tons; 10.5 short tons)
Adhesive weight47.5 t (46.7 long tons; 52.4 short tons)
Empty weight47.5 t (46.7 long tons; 52.4 short tons)
Service weight64.5 t (63.5 long tons; 71.1 short tons)
Fuel typeCoal
Fuel capacity4.0 t (3.9 long tons; 4.4 short tons)
Water cap.8.0 m3 (1,760 imp gal; 2,110 US gal)
Firebox:​
 • Grate area2.8 m2 (30 sq ft)
Boiler:
​
 • Pitch2,500 mm (8 ft 2+3⁄8 in)
 • Tube plates3,200 mm (10 ft 6 in)
 • Small tubes44.5 mm (1+3⁄4 in), 114 off
 • Large tubes121 mm (4+3⁄4 in), 32 off
Boiler pressure14 bar (14.3 kgf/cm2; 203 psi)
Feedwater heaterMixer-preheater
Heating surface:​
 • Firebox10.4 m2 (112 sq ft)
 • Tubes49.7 m2 (535 sq ft)
 • Flues35.4 m2 (381 sq ft)
 • Total surface95.5 m2 (1,028 sq ft)
Superheater:
​
 • Heating area30.0 m2 (323 sq ft)
CylindersTwo, outside
Cylinder size500 mm × 500 mm (19+11⁄16 in × 19+11⁄16 in)
Valve gearHeusinger with Kuhn slides
Loco brakeKe G-P mZ
Train brakesHardy vacuum brake, converted to Knorr compressed air brake
CouplersEqualising lever coupler [de]; in Eisfeld: Janney
Performance figures
Maximum speed40 km/h (25 mph)
Indicated power700–750 PS (515–552 kW; 690–740 hp)
Tractive effort102.9 kN (23,100 lbf)
Career
Operators
NumbersDR: 99 231 – 99 247
from 1970: 99 7231 – 99 7247

The engines of DR Class 99.23 are metre gauge tank locomotives, that were procured by the Deutsche Reichsbahn (DR) in East Germany from 1954 to 1956. When they entered service they had operating numbers 99 231–99 247. Today they are numbered 99 7231–99 7247.

History

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A total of 17 locomotives were bought by the DR between 1954 and 1956 for the railways of the Harzquerbahn and Brockenbahn, and for the line from Eisfeld to Schönbrunn to replace much of the outdated fleet. Four locomotives were built for the USSR in 1956, but their ultimate fate is unknown. The first seven units (99 231 to 99 237) were originally equipped with two Krauss-Helmholtz bogies. Due to problems with curve running, the engines in the second series were given Beugniot levers between the first and second coupled axles in addition to the Krauss-Helmholtz bogies[1] (according to other sources also a Schwartzkopff-Eckhardt II bogie[2][3][4][5]).

The locomotives of the first series were subsequently modified with Beugniot levers, some in the early 1960s, others in 1973/74 (on the Harz lines). The thinner wheel flanges of the driving wheels were completely removed later to achieve better curve running, resulting in the second series not having a rigid wheelbase.[2] The drive was applied to the third coupled axle, the locomotives had Heusinger valve gear with unsprung Müller balanced slide valves and, later, Trofimoff valves.

These Neubaulokomotiven were a fully welded development of the standard locomotives (Einheitsloks) of the DRG Class 99.22. In contrast to those, the 99.23-24s had mixer-preheaters and plate frames. However, the latter caused maintenance difficulties from the outset due to cracks and distortion. 10 locomotives (99 7232, 7240, 7245, 7239, 7236, 7234, 7237, 7241, 7243, 7247) were equipped from 2004 onward with a redesigned plate frame and 5 of those (99 7232, 7240, 7245, 7239, 7236) with new, welded steam cylinders. The 17 DR engines are all extant and based in the Harz; some however are no longer working.

The 17 German engines were converted to primary oil-firing between 1977 and 1983, and together with the DRG Class 99.22 are the most powerful German narrow gauge steam locomotives ever constructed. They were later converted back to coal-firing and are primarily used on the line up to the Brocken from Wernigerode.

Their operating numbers changed from 99 231 et seq to 99 7231 et seq on the introduction of computerised numbers in 1970 and then again to 99 0231 et seq on conversion to oil-firing. The computer numbers are still valid because the HSB retains those allocated in the 1970 DR renumbering scheme.

The engines can carry 4 tonnes (4 long tons; 4 short tons) of coal and 8,000 litres (1,760 imperial gallons; 2,113 US gallons) of water.

Locomotives

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  • 99 7231: out of service since 2001
  • 99 7232: working, new frame
  • 99 7233: out of service since 1999
  • 99 7234: working, new frame
  • 99 7235: out of service since 2020
  • 99 7236: working, new frame
  • 99 7237: working, new frame
  • 99 7238: working
  • 99 7239: working, new frame
  • 99 7240: working, new frame
  • 99 7241: working, new frame
  • 99 7242: out of service since 2010
  • 99 7243: working, new frame
  • 99 7244: working, undergoing conversion to oil-firing
  • 99 7245: working, new frame
  • LKM 134023: built for & lost in the USSR
  • LKM 134024: built for & lost in the USSR
  • LKM 134025: built for & lost in the USSR
  • LKM 134026: built for & lost in the USSR
  • 99 7246: out of service since 1996
  • 99 7247: working, new frame
[edit]
  • 99 7232
    99 7232
  • 99 7234
    99 7234
  • 99 7237
    99 7237

See also

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Wikimedia Commons has media related to DR Class 99.23-24.

References

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  1. ^ Weisbrod/Wiegard/Müller/Petznik: Deutsches Lok-Archiv: Dampflokomtiven 4. Baureihe 99, Transpress Berlin 1995, ISBN 3-344-70903-8
  2. ^ a b EK-Themen 18, Brockenlok 99.22, Eisenbahn-Kurier, Freiburg 1995
  3. ^ Obermayer: Taschenbuch Deutsche Schmalspur-Dampflokomotiven. Franckh'sche Verlagshandlung, Stuttgart 1971, ISBN 3-440-03818-1
  4. ^ Kühne. Alles über DDR-Dampfloks, Transpress, Stuttgart 2008, ISBN 978-3-613-71335-2
  5. ^ Website of the Freundeskreises Selketalbahn (see below)
  • Obermayer, Horst J. Taschenbuch Deutsche Schmalspur-Dampflokomotiven, Franckh'sche Verlagshandlung, Stuttgart, ISBN 3-440-03818-1, 1971, pp. 60–61.
  • Vetter, Klaus J. Das große Handbuch deutscher Lokomotiven, Bruckmann, München, ISBN 3-7654-3764-6, 2001, pp 191–192.
  • Weisbrod, Manfred; Petznik, Wolfgang (1981). Dampflokomotiven deutscher Eisenbahnen, Baureihe 97–99 (EFA 1.4) (in German) (2nd ed.). Düsseldorf: Alba. pp. 137–141, 207. ISBN 3-87094-087-5.
  • Weisbrod, Manfred; Wiegard, Hans; Müller, Hans; Petznick, Wolfgang. Deutsches Lok-Archiv: Dampflokomotiven 4 (Baureihe 99), Transpress, Berlin,ISBN 3-344-70903-8, 1995, pp 53–57.


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