Donnerbüchse

Four-wheeled, standard, open coach
*Donnerbüchse*
"Thunderbox"
Four-wheeled, standard, open coach; Donnerbüchse; "Thunderbox"
	A Thunderbox on a South German Railway Museum special service at Crailsheim, December 2007
Constructed	1921 to 1931
Number built	8255 passenger coaches; 917 luggage vans;
Specifications
Car length	13,920 mm (45 ft 8 in); Bi-29: 14,040 mm (46 ft 3⁄4 in);
Width	Wooden type: 3,000 mm (9 ft 10+1⁄8 in); Austauschbauart: 3,090 mm (10 ft 1+5⁄8 in); Bi-29: 2,996 mm (9 ft 10 in); Luggage van: 2,855 mm (9 ft 4+3⁄8 in);
Wheel diameter	1,000 mm (3 ft 3+3⁄8 in)
Maximum speed	90 km/h (56 mph)
Weight	Wooden type: 18.0 t (17.7 long tons; 19.8 short tons); Iron type: 17.6–20.0 t (17.3–19.7 long tons; 19.4–22.0 short tons); All steel: 19.5–21.4 t (19.2–21.1 long tons; 21.5–23.6 short tons); Luggage van: 18.4–20.5 t (18.1–20.2 long tons; 20.3–22.6 short tons);

The German term Donnerbüchse (plural: Donnerbüchsen, formerly Donnerwagen) means "thunderbox" and is the nickname for the four-wheeled, open, passenger coaches, built from 1921 onwards, that served with the Deutsche Reichsbahn. In contrast to their predecessors, they were made entirely of iron or steel. The name comes from the loud rumbling of these coaches as a result of their lack of damping. Even the immediate forerunners of these wagons were given the name despite their wooden construction. In the early days, they were also called Ackermann'sche Donnerbüchse ("Ackermann's thunderboxes") after the departmental head responsible for them in the Ministry of Transport.

Four-wheeled, standard, open coach Donnerbüchse "Thunderbox"
A Thunderbox on a South German Railway Museum special service at Crailsheim, December 2007
Constructed	1921 to 1931
Number built	8255 passenger coaches 917 luggage vans
Specifications
Car length	13,920 mm (45 ft 8 in) Bi-29: 14,040 mm (46 ft 3⁄4 in)
Width	Wooden type: 3,000 mm (9 ft 10+1⁄8 in) Austauschbauart: 3,090 mm (10 ft 1+5⁄8 in) Bi-29: 2,996 mm (9 ft 10 in) Luggage van: 2,855 mm (9 ft 4+3⁄8 in)
Wheel diameter	1,000 mm (3 ft 3+3⁄8 in)
Maximum speed	90 km/h (56 mph)
Weight	Wooden type: 18.0 t (17.7 long tons; 19.8 short tons) Iron type: 17.6–20.0 t (17.3–19.7 long tons; 19.4–22.0 short tons) All steel: 19.5–21.4 t (19.2–21.1 long tons; 21.5–23.6 short tons) Luggage van: 18.4–20.5 t (18.1–20.2 long tons; 20.3–22.6 short tons)