DRG Class 04

DRG Class 04 later DRG Class 02.1
04 001 in 1932
Type and origin Power type Steam Builder Krupp Serial number 1194–1195 Build date 1932 Total produced 2
Specifications Configuration: ​  • Whyte 4-6-2  • UIC 2′C1′ h4v  • German S 36.18 Driver Divided: inside high-pressure cylinders to first coupled axle, outside low-pressure cylinders to second Gauge 1,435 mm (4 ft 8+1⁄2 in) Leading dia. 1,000 mm (39+3⁄8 in) Driver dia. 2,000 mm (78+3⁄4 in) Trailing dia. 1,250 mm (49+1⁄4 in) Tender wheels 1,000 mm (39+3⁄8 in) Wheelbase: ​  • Axle spacing (Asymmetrical) 2,200 mm (7 ft 2+5⁄8 in) + 1,800 mm (5 ft 10+7⁄8 in) + 2,250 mm (7 ft 4+5⁄8 in) + 2,250 mm (7 ft 4+5⁄8 in) + 3,500 mm (11 ft 5+3⁄4 in) =  • Engine 12,000 mm (39 ft 4+1⁄2 in)  • Tender 1,900 mm (6 ft 2+3⁄4 in) + 1,900 mm (6 ft 2+3⁄4 in) + 1,900 mm (6 ft 2+3⁄4 in) = 5,700 mm (18 ft 8+3⁄8 in)  • incl. tender 20,225 mm (66 ft 4+1⁄4 in) Length: ​  • Over headstocks 22,605 mm (74 ft 2 in)  • Over buffers 23,905 mm (78 ft 5+1⁄8 in) Height 4,550 mm (14 ft 11+1⁄8 in) Axle load 18.78–18.79 tonnes (18.48–18.49 long tons; 20.70–20.71 short tons) Adhesive weight 54.9–57.6 tonnes (54.0–56.7 long tons; 60.5–63.5 short tons) Empty weight 97.0–118.5 tonnes (95.5–116.6 long tons; 106.9–130.6 short tons) Service weight 106.3–129.9 tonnes (104.6–127.8 long tons; 117.2–143.2 short tons) Tender type 2′2′ T 32 Fuel type Coal Fuel capacity 10 tonnes (9.8 long tons; 11 short tons) Water cap. 32 m3 (7,000 imp gal; 8,500 US gal) Firebox: ​  • Grate area 4.10 m2 (44.1 sq ft) Boiler: ​  • Pitch 3,100 mm (10 ft 2 in) +  • Tube plates 04 001: 5,800 mm (19 ft 3⁄8 in) 04 002: 6,800 mm (22 ft 3+3⁄4 in)  • Small tubes 04 001: 54 mm (2+1⁄8 in), 84 off 04 002: 70 mm (2+3⁄4 in), 75 off  • Large tubes 04 001: 143 mm (5+5⁄8 in), 38 off 04 002: 171 mm (6+3⁄4 in), 24 off Boiler pressure 25 bar (25.5 kgf/cm2; 363 psi) Heating surface: ​  • Firebox 20 m2 (220 sq ft)  • Tubes 04 001: 75.1 m2 (808 sq ft) 04 002: 104.3 m2 (1,123 sq ft)  • Flues 04 001: 93.5 m2 (1,006 sq ft) 04 002: 82.5 m2 (888 sq ft)  • Total surface 04 001: 188.6 m2 (2,030 sq ft) 04 002: 206.8 m2 (2,226 sq ft) Superheater: ​  • Heating area 04 001: 88.0 m2 (947 sq ft) 04 002: 84.6 m2 (911 sq ft) Cylinders Four, compound: HP inside, LP outside High-pressure cylinder 350 mm × 660 mm (13+3⁄4 in × 26 in) Low-pressure cylinder 520 mm × 660 mm (20+1⁄2 in × 26 in) Valve gear Heusinger (Walschaerts)
Performance figures Maximum speed 130 km/h (81 mph) Indicated power 2,100–2,320 PS (1,540–1,710 kW; 2,070–2,290 hp) (depending on build state)
Career Operators Deutsche Reichsbahn Numbers DRG 04 001 and 04 002 from 1935: 02 101 and 02 102 Retired 1939 Disposition Both scrapped

The two German Class 04 steam locomotives were experimental engines with the Deutsche Reichsbahn, that were derived from the Class 03 standard locomotives (Einheitsloks).

In 1932, the Deutsche Reichsbahn tried to raise boiler overpressures from 156.9 to 245.1 N/cm² (227.6 to 355.5 psi) by using high-tensile steel. These engines, built by the firm of Krupp, were initially tested at the Grunewald Locomotive Testing Office. With a specific steam consumption value of 5.2 kg/PSh with respect to their indicated output, the locomotives clearly undercut the very low steam consumption value of the Class 03 by over 1 kg/PSh. The coal consumption based on the effective power at the coupling hook, was 0.96 kg/PSh compared with 1.13 kg/PSh on the 03.^[1]

The medium-pressure boilers did not prove to be stable, and after a short time damage occurred to the firebox. Since the locomotives did not meet expectations even after modifications and repairs, the permissible boiler overpressure was finally reduced to 20 atmospheres in 1935 and they were added to the operating portfolio with the company numbers 02 101 and 02 102. They were then intended to be used in regular train service from the Hamburg-Altona depot, but since they had no experience with four-cylinder compound locomotives there, they were handed over to the Hof depot in 1936. Due to a lack of water, the boiler of 02 101 exploded on 3 April 1939,^[2] whereupon both engines were decommissioned and were scrapped in 1940.

The engines were equipped with a 2′2′ T 32 standard tender.

• List of DRG locomotives and railcars
• List of boiler explosions

• Hütter, Ingo (2009). Die Dampflokomotiven der Baureihen 01 bis 45 der DRG, DRB, DB, und DR (in German). Werl: DGEG Medien. pp. 74, 90. ISBN 978-3-937189-45-1.
• Weisbrod, Manfred; Müller, Hans; Petznik, Wolfgang (1976). Dampflokomotiven deutscher Eisenbahnen, Baureihe 01–39 (EFA 1.1) (in German) (3rd ed.). Düsseldorf: Alba Buchverlag. pp. 53–55, 244–245. ISBN 3-87094-081-6.