The German DRG Class 02 (Baureihe 02 or BR 02) engines were standard (Einheitslokomotiven) express train locomotives with the Deutsche Reichsbahn-Gesellschaft. Number 02 001 was the first Einheitsdampflokomotive in the DRG to be completed.

DRG Class 02
02 008 in June 1932
Type and origin Power type Steam Builder Henschel & Sohn (8) Maffei (2) Serial number Henschel 20460–20467 Maffei 5621–5622 Build date 1925–1926 Total produced 10
Specifications Configuration: ​  • Whyte 4-6-2  • UIC 2′C1′ h4v  • German S 36.20 Driver 2nd coupled axle for all cylinders Gauge 1,435 mm (4 ft 8+1⁄2 in) Leading dia. 0,850 mm (33+1⁄2 in) Driver dia. 2,000 mm (78+3⁄4 in) Trailing dia. 1,250 mm (49+1⁄4 in) Wheelbase: ​  • Axle spacing (Asymmetrical) 2,200 mm (7 ft 2+5⁄8 in) + 1,800 mm (5 ft 10+7⁄8 in) + 2,300 mm (7 ft 6+1⁄2 in) + 2,300 mm (7 ft 6+1⁄2 in) + 3,800 mm (12 ft 5+5⁄8 in)  • incl. tender 20,320 mm (66 ft 8 in) Length: ​  • Over buffers 23,750 mm (77 ft 11 in) Height 4.550 m (14 ft 11+1⁄8 in) Axle load 20.1 tonnes (19.8 long tons; 22.2 short tons) Adhesive weight 60.3 tonnes (59.3 long tons; 66.5 short tons) Empty weight 103.9 tonnes (102.3 long tons; 114.5 short tons) Service weight 113.5 tonnes (111.7 long tons; 125.1 short tons) Tender type 2′2 T 32 (2′2 T 30) Fuel type Coal Fuel capacity 10.0 tonnes (9.8 long tons; 11.0 short tons) Water cap. 32 or 30 m3 (7,040 or 6,600 imp gal; 8,450 or 7,930 US gal) Firebox: ​  • Grate area 4.41 m2 (47.5 sq ft) Boiler: ​  • Pitch 3,100 mm (10 ft 2 in)  • Tube plates 5,800 mm (19 ft 3⁄8 in)  • Small tubes 54 mm (2+1⁄8 in), 129 off  • Large tubes 143 mm (5+5⁄8 in), 43 off Boiler pressure 16 bar (16.3 kgf/cm2; 232 psi) Heating surface: ​  • Firebox 17.0 m2 (183 sq ft)  • Tubes 115.18 m2 (1,239.8 sq ft)  • Flues 105.38 m2 (1,134.3 sq ft)  • Total surface 237.56 m2 (2,557.1 sq ft) Superheater: ​  • Heating area 100.0 m2 (1,076 sq ft) Cylinders Four (compound): two high-pressure (HP) inside, two low-pressure (LP) outside High-pressure cylinder 460 mm × 660 mm (18+1⁄8 in × 26 in) Low-pressure cylinder 720 mm × 660 mm (28+3⁄8 in × 26 in) Valve gear Walschaerts (Heusinger) Train heating Steam Loco brake Knorr single-chamber, compressed air brakes, operating on front of all coupled wheels
Performance figures Maximum speed fwds: 130 km/h (81 mph) bwds: 50 km/h (31 mph) Indicated power 2,300 PS (1,690 kW; 2,270 hp)
Career Numbers DRG 02 001 to 02 010 Disposition Rebuilt to DRG Class 01 (1937–1942)

In procuring a standard express train steam locomotive, the Deutsche Reichsbahn carried out a comparison between a superheated two-cylinder type (the DRG Class 01) and a four-cylinder compound locomotive (the Class 02). Ten examples of each type were built from 1925, and the Class 02 vehicles were given operating numbers 02 001 – 02 010. The first eight engines were manufactured in 1925 by the firm of Henschel, two more were built in 1926 by Maffei.

Because the Class 02 steam engines were badly designed, the compound engine could only produce a high level of power at speeds of over 70 km/h. In addition, below 100 PSi its steam consumption was higher than that of the Class 01.

Compared with the Class 01s, these engines had a complicated, and therefore maintenance-intensive, drive; as a result no more were ordered. From 1937 to 1942 the vehicles were successively converted to two-cylinder simple operation and regrouped as Class 01s with the new numbers 01 011 and 01 233 to 01 241.

The first eight engines were equipped with 2'2' T 30 tenders; the other two with 2'2 T 32 tenders. Later on, the second tender was coupled to all of the first eight engines as well.