DB Class 78.10

The two German steam locomotives of DB Class 78.10, operated by the Deutsche Bundesbahn, were rebuilds based on two Prussian P 8 engines which were converted by the firm of Krauss-Maffei and the Minden repair shop. The aim was to improve the acceleration performance of the vehicles, especially for duties on suburban lines and city (Stadtbahn) lines.

DB Class 78.10
Number(s)	DB 78 1001 – 78 1002
Quantity	2
Manufacturer	Krauss-Maffei
Year(s) of manufacture	1951
Retired	1961
Wheel arrangement	4-6-4T
Axle arrangement	2′C2′ h2t
Track gauge	1,435 mm (4 ft 8 ^1⁄2 in)
Length over buffers	17,237 mm (56 ft 6 ^1⁄2 in)
Height	4,550 mm (14 ft 11 ^1⁄8 in)
Overall wheelbase	14,070 mm (46 ft 2 in)
Empty weight	81 tonnes (80 long tons; 89 short tons)
Service weight	110.0 tonnes (108.3 long tons; 121.3 short tons)
Adhesive weight	51.1 tonnes (50.3 long tons; 56.3 short tons)
Axle load	17.3 tonnes (17.0 long tons; 19.1 short tons)
Top speed	100 km/h (62 mph)
Indicated Power	868 kW (1,180 PS; 1,164 hp)
Driving wheel diameter	1,750 mm (5 ft 8 ^7⁄8 in)
Leading wheel diameter	1,000 mm (3 ft 3 ^3⁄8 in)
Trailing wheel diameter	1,000 mm (3 ft 3 ^3⁄8 in)
Valve gear	Walschaerts (Heusinger)
Cylinder bore	575 mm (22 ^5⁄8 in)
Piston stroke	630 mm (24 ^13⁄16 in)
Boiler Overpressure	12 bar (1.2 MPa; 170 psi)
No. of heating tubes	123
No. of smoke tubes	26
Heating tube length	4,700 mm (15 ft 5 in)
Grate area	2.58 m^2 (27.8 sq ft)
Superheater area	58.90 m^2 (634.0 sq ft)
Evaporative heating area	143.28 m^2 (1,542.3 sq ft)
Water capacity	17 m^3 (600 cu ft) or 17,000 litres (3,700 imp gal; 4,500 US gal)
Fuel	5 tonnes (4.9 long tons; 5.5 short tons)
Brakes	Compressed-air brake

The running gear, drive and boilers of both locomotives, which originally had the running numbers 38 2919 and 38 2990, remained virtually unchanged. The driver's cab was redesigned. A short tender was added which was coupled to the engine with a shaft and improved the riding qualities when running in reverse. The locomotives were classed as tank engines and initially worked in the Munich area, later in Augsburg and finally by Lake Constance. They remained the only ones of their type and were retired as early as 1961.

Neither of the two DB Class 78.10 locomotives has been preserved.