DR Class 99.23-24

Specifications
Specifications
Configuration:;
• Whyte	2-10-2T
• UIC	1′E1′ h2t
• German	K 57.10
Gauge	1,000 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) =;
• Engine	8,700 mm (342+1⁄2 in)
Length:;
• Over couplers	11,730 mm (461+3⁄4 in)
• Over headstocks	11,100 mm (437 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 t (9.3 long tons; 10.5 short tons)
Adhesive weight	47.5 t (46.7 long tons; 52.4 short tons)
Empty weight	47.5 t (46.7 long tons; 52.4 short tons)
Service weight	64.5 t (63.5 long tons; 71.1 short tons)
Fuel type	Coal
Fuel capacity	4.0 t (3.9 long tons; 4.4 short tons)
Water cap.	8.0 m3 (1,760 imp gal; 2,110 US gal)
Firebox:
• Grate area	2.8 m2 (30 sq ft)
Boiler:;
• Pitch	2,500 mm (8 ft 2+3⁄8 in)
• Tube plates	3,200 mm (10 ft 6 in)
• Small tubes	44.5 mm (1+3⁄4 in), 114 off
• Large tubes	121 mm (4+3⁄4 in), 32 off
Boiler pressure	14 bar (14.3 kgf/cm2; 203 psi)
Feedwater heater	Mixer-preheater
Heating surface:
• Firebox	10.4 m2 (112 sq ft)
• Tubes	49.7 m2 (535 sq ft)
• Flues	35.4 m2 (381 sq ft)
• Total surface	95.5 m2 (1,028 sq ft)
Superheater:;
• Heating area	30.0 m2 (323 sq ft)
Cylinders	Two, outside
Cylinder size	500 mm × 500 mm (19+11⁄16 in × 19+11⁄16 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 coupler; in Eisfeld: Janney

Type and origin
Type and origin
Power type	Steam
Builder	VEB Lokomotivbau "Karl Marx" Babelsberg
Serial number	134008–134028
Build date	1954–1956
Total produced	21

DR Class 99.23–24
DR Class 99.23–24
	99 7243-1 in 2006
Power type
Type and origin
Power type	Steam
Builder	VEB Lokomotivbau "Karl Marx" Babelsberg
Serial number	134008–134028
Build date	1954–1956
Total produced	21
Configuration:;
Specifications
Configuration:;
• Whyte	2-10-2T
• UIC	1′E1′ h2t
• German	K 57.10
Gauge	1,000 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) =;
• Engine	8,700 mm (342+1⁄2 in)
Length:;
• Over couplers	11,730 mm (461+3⁄4 in)
• Over headstocks	11,100 mm (437 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 t (9.3 long tons; 10.5 short tons)
Adhesive weight	47.5 t (46.7 long tons; 52.4 short tons)
Empty weight	47.5 t (46.7 long tons; 52.4 short tons)
Service weight	64.5 t (63.5 long tons; 71.1 short tons)
Fuel type	Coal
Fuel capacity	4.0 t (3.9 long tons; 4.4 short tons)
Water cap.	8.0 m3 (1,760 imp gal; 2,110 US gal)
Firebox:
• Grate area	2.8 m2 (30 sq ft)
Boiler:;
• Pitch	2,500 mm (8 ft 2+3⁄8 in)
• Tube plates	3,200 mm (10 ft 6 in)
• Small tubes	44.5 mm (1+3⁄4 in), 114 off
• Large tubes	121 mm (4+3⁄4 in), 32 off
Boiler pressure	14 bar (14.3 kgf/cm2; 203 psi)
Feedwater heater	Mixer-preheater
Heating surface:
• Firebox	10.4 m2 (112 sq ft)
• Tubes	49.7 m2 (535 sq ft)
• Flues	35.4 m2 (381 sq ft)
• Total surface	95.5 m2 (1,028 sq ft)
Superheater:;
• Heating area	30.0 m2 (323 sq ft)
Cylinders	Two, outside
Cylinder size	500 mm × 500 mm (19+11⁄16 in × 19+11⁄16 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 coupler; in Eisfeld: Janney
Maximum speed
Performance figures
Maximum speed	40 km/h (25 mph)
Indicated power	700–750 PS (515–552 kW; 690–740 hp)
Tractive effort	102.9 kN (23,100 lbf)
Operators
Career
Operators	formerly: Deutsche Reichsbahn (GDR) (17) / Soviet Railways (4); now: Harzer Schmalspurbahnen GmbH (21);
Numbers	DR: 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.