DR Class 99.23-24

DR Class 99.23-24
99 7243
Type and origin Builder VEB Lokomotivbau "Karl Marx" Babelsberg Build date 1954–1956 Total produced 17
Specifications Configuration: ​  • Whyte 2-10-2T  • German K 57.10 Gauge 1,000 mm (3 ft 3+3⁄8 in) metre gauge Driver dia. 1,000 mm (3 ft 3+3⁄8 in) Carrying wheel diameter 550 mm (1 ft 9+5⁄8 in) Wheelbase: ​  • Overall 8,700 mm (342+1⁄2 in) Length: ​  • Over buffers 12,500 mm (41 ft 1⁄4 in) Width 2,645 mm (8 ft 8+1⁄8 in) Height 3,650 mm (11 ft 11+11⁄16 in) Axle load 9.5 tonnes (9.3 long tons; 10.5 short tons) Adhesive weight 47.5 tonnes (46.7 long tons; 52.4 short tons) Empty weight 47.5 tonnes (46.7 long tons; 52.4 short tons) Service weight 60.5 tonnes (59.5 long tons; 66.7 short tons) Fuel capacity Coal: 4 tonnes (3.9 long tons; 4.4 short tons) Water cap. 8 m3 (280 cu ft) or 8,000 litres (1,800 imp gal; 2,100 US gal) Firebox: ​  • Grate area 2.8 m2 (30 sq ft) Boiler: ​  • Small tubes 114  • Large tubes 32 Boiler pressure 14 bar (1.40 MPa; 203 psi)} Heating surface: ​  • Firebox 10.4 m2 (112 sq ft)  • Total surface 95.5 m2 (1,028 sq ft) Superheater: ​  • Heating area 30 m2 (320 sq ft) Cylinders 2 Cylinder size 500 mm (19.69 in) Piston stroke 500 mm (19.69 in) Valve gear Heusinger with Kuhn slides Loco brake Ke G-P mZ Train brakes Hardy vacuum brake, converted to Knorr compressed air brake Couplers Equalising lever couplers (de:Balancierhebelkupplung); in Eisfeld: Janney
Performance figures Maximum speed 40 km/h (25 mph) Indicated power 515 kW (700 PS; 691 hp) Tractive effort: ​  • Starting 102.9 kN (23,100 lbf)
Career Numbers 99 231 – 99 247 from 1970: 99 7231 – 99 7247

The engines of DR Class 99.23 are metre gauge steam 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

Between 1954 and 1956 a total of 17 locomotives were bought by the DR for the railways of the Harzquerbahn and Brockenbahn and for the line from Eisfeld to Schönbrunn. They replaced much of the very old fleet. 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. (according to other sources also a Schwartzkopff-Eckhardt II bogie ). 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 in order to achieve better curve running. Certainly the engines in the second series did not have a rigid wheelbase.

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 evolutionary 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. To date five locomotives (the present-day 99 7232, 7240, 7245, 7239, 7236) were equipped from 2004 onwards with a new, redesigned plate frames and new, welded, steam cylinders. More should follow. All the engines still exist and are based in the Harz; some however are no longer working.

The engines were converted between 1977 and 1983 to primary oil-firing and are the most powerful German narrow gauge steam locomotives ever to have been built. They 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 vehicles can carry 4.0 tonnes of coal and 8.0 m³ of water.

Locomotives

• 99 7231: out of service
• 99 7232: working, new frame
• 99 7233: out of service
• 99 7234: working
• 99 7235: working
• 99 7236: working, new frame
• 99 7237: working
• 99 7238: out of service
• 99 7239: working, new frame
• 99 7240: working, new frame
• 99 7241: working
• 99 7242: working
• 99 7243: working
• 99 7244: out of service
• 99 7245: working, new frame
• 99 7246: out of service
• 99 7247: working

Photo gallery

• 
  99 7232
• 
  99 7234
• 
  99 7237

Literature

• 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.
• Vetter, Klaus J. Das große Handbuch deutscher Lokomotiven, Bruckmann, München, ISBN 3-7654-3764-6, 2001, pp 191–192.
• Obermayer, Horst J. Taschenbuch Deutsche Schmalspur-Dampflokomotiven, Franckh'sche Verlagshandlung, Stuttgart, ISBN 3-440-03818-1, 1971, pp. 60–61.

See also

• List of East German Deutsche Reichsbahn locomotives and railbuses
• Neubaulok

External links

• Freundeskreis Selketalbahn website (in German)
• HSB website (in German)