Indian locomotive class AP

BESA class AP
EIR locomotive No. 120, built by North British Locomotive Company
Type and origin
Power typeSteam
DesignerBritish Engineering Standards Association
Builder
Total produced58
Specifications
Configuration:
 • Whyte4-4-2
 • UIC2B1 n2
Gauge1,676 mm (5 ft 6 in)
Leading dia.3 ft 7 in (1,092 mm)
Driver dia.6 ft 6 in (1,981 mm)
Wheelbase:
 • Leading7 ft 0 in (2,134 mm)
 • Coupled6 ft 9 in (2,057 mm)
 • incl. tender50 ft 7+12 in (15,430 mm) (3000-gal tender)
Length:
 • Over buffers60 ft 6+78 in (18,463 mm) (3000-gal tender)
Width9 ft 6 in (2,896 mm)
Height13 ft 6 in (4,115 mm)
Axle load17.25 long tons (17.53 t)
Service weight65.00 long tons (66.04 t)
Tender weight39.50 long tons (40.13 t)
Water cap.3,000 or 4,000 or 4,500 imp gal (14,000 or 18,000 or 20,000 L; 3,600 or 4,800 or 5,400 US gal)
Firebox:
 • Grate area32 sq ft (3.0 m2)
Boiler pressure180 psi (12.4 bar; 12.7 kgf/cm2)
Heating surface:
 • Firebox1,057 sq ft (98.2 m2)
 • Tubes1,880 sq ft (175 m2)
 • Total surface2,037 sq ft (189.2 m2)
CylindersTwo, outside
Cylinder size19 in × 26 in (483 mm × 660 mm)
Career
Operators

The Class AP was a broad gauge tender steam locomotive introduced around 1907 for passenger trains on the railways in British India. Its class designation, AP, stands for Atlantic Passenger Locomotive, where Atlantic refers to the wheel arrangement of the same name. It was one of the BESA locomotives developed by the British Engineering Standards Committee, later called the British Engineering Standards Association (BESA).