Bavarian BB I

The BB I was a steam locomotive with the Royal Bavarian State Railways (Königlich Bayerische Staatsbahn).

Bavarian BB I
Number(s)	Bavaria: 2100
Quantity	1
Manufacturer	Maffei
Year(s) of manufacture	1896
Retired	1924
Wheel arrangement	0-4-4-0
Axle arrangement	B′B n4v
Track gauge	1,435 mm (4 ft 8 1⁄2 in)
Length over buffers	16,991 or 17,894 mm (55 ft 9 in or 58 ft 8 1⁄2 in)
Service weight	55.6 t (54.7 long tons; 61.3 short tons)
Adhesive weight	55.6 t (54.7 long tons; 61.3 short tons)
Axle load	14.2 t (14.0 long tons; 15.7 short tons)
Top speed	45 or 65 km/h (28 or 40 mph)
Driving wheel diameter	1,340 millimetres (4 ft 4 3⁄4 in)
No. of cylinders	4
LP cylinder bore	635 mm (25 in)
HP cylinder bore	415 mm (16 5⁄16 in)
Piston stroke	630 mm (24 13⁄16 in)
Boiler Overpressure	14 kgf/cm2 (1.37 MPa; 199 psi)
Grate area	2.07 m2 (22.3 sq ft)
Evaporative heating area	123.00 m2 (1,324.0 sq ft)
Tender	Bavarian 3 T 13,8 2'2' T 18
Water capacity	13.8 or 18.0 m3 (3,000 or 4,000 imp gal; 3,600 or 4,800 US gal)

This one-off loco would have been given the operating number 55 7101 by the Reichsbahn in their initial renumbering plan, but in the final one it did not appear as it had been retired in 1924. It can be seen in section today in the Nuremberg Transport Museum.

The engine was initially equipped with a Bavarian 3 T 13,8 tender, later replaced by a Class 2'2' T 18.