Soviet locomotive class AA20

Specifications
Specifications
Configuration:;
• Whyte	4-14-4
Gauge	1,524 mm (5 ft)
Leading dia.	760 mm (29.92 in)
Driver dia.	1,600 mm (62.99 in)
Trailing dia.	1,050 mm (41.34 in)
Length	33,730 mm (110.66 ft)
Axle load	20 t (20 long tons; 22 short tons)
Fuel type	Coal
Firebox:
• Grate area	12 m2 (130 sq ft)
Boiler pressure	17 kgf/cm2 (1.67 MPa; 242 psi)
Superheater:;
• Heating area	174 m2 (1,870 sq ft)
Cylinders	Two, outside
Cylinder size	740 mm × 810 mm (29.13 in × 31.89 in); bore x stroke

Type and origin
Type and origin
Power type	Steam
Builder	Krupp; Voroshilovgrad Locomotive Factory
Build date	1934
Total produced	1

Soviet locomotive class AA20
Soviet locomotive class AA20
	А. Андреев, the only 4-14-4 locomotive ever built
Power type
Type and origin
Power type	Steam
Builder	Krupp; Voroshilovgrad Locomotive Factory
Build date	1934
Total produced	1
Configuration:;
Specifications
Configuration:;
• Whyte	4-14-4
Gauge	1,524 mm (5 ft)
Leading dia.	760 mm (29.92 in)
Driver dia.	1,600 mm (62.99 in)
Trailing dia.	1,050 mm (41.34 in)
Length	33,730 mm (110.66 ft)
Axle load	20 t (20 long tons; 22 short tons)
Fuel type	Coal
Firebox:
• Grate area	12 m2 (130 sq ft)
Boiler pressure	17 kgf/cm2 (1.67 MPa; 242 psi)
Superheater:;
• Heating area	174 m2 (1,870 sq ft)
Cylinders	Two, outside
Cylinder size	740 mm × 810 mm (29.13 in × 31.89 in); bore x stroke
Maximum speed
Performance figures
Maximum speed	70 km/h (43 mph)
Tractive effort	320 kN (71,940 lbf)
Operators
Career
Operators	Soviet Railways
Locale	Soviet Union
First run	1935
Scrapped	1960
Disposition	Scrapped

The SZD Class AA20 was a one-off experimental 4-14-4 steam locomotive constructed in the Soviet Union by Krupp and the Voroshilovgrad Locomotive Factory in 1934 for the Sovetskie Zheleznye Dorogi (SŽD). Two locomotives were set to be built, but due to the construction of the railway's more powerful FD Class, only AA20-1 was built, leaving the second AA20 incomplete.