British Rail Class 81

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British Railways AL1 British Rail Class 81
81004 at Birmingham New Street in 1984
Type and origin Power type Electric Builder Associated Electrical Industries at Birmingham Railway Carriage and Wagon Company Build date 1959–1964 Total produced 25
Specifications Configuration: ​  • AAR B-B  • UIC Bo′Bo′  • Commonwealth Bo-Bo Gauge 4 ft 8+1⁄2 in (1,435 mm) standard gauge Bogies Fabricated steel, Alsthom suspension[1] Wheel diameter 4 ft 0 in (1.219 m)[1] Wheelbase 42 ft 3 in (12.88 m)[1] ​  • Bogie 10 ft 9 in (3.28 m)[1] Pivot centres 31 ft 6 in (9.60 m)[2] Length: ​  • Over beams 56 ft 6 in (17.22 m)[1] Width 8 ft 8+1⁄2 in (2.65 m)[1] Height: ​  • Pantograph 13 ft 0+9⁄16 in (3.977 m)[2]  • Body height 12 ft 4+1⁄4 in (3.77 m)[1] Axle load 20 long tons 4 cwt (20.5 t)[2] Loco weight 79.60 long tons (80.9 t; 89.2 short tons) Electric system/s 25 kV AC Catenary Current pickup(s) Stone-Faiveley[1] ‘V’-type pantograph, 2 off (later 1 off) Traction motors 4 × AEI 189 6-pole Alsthom Quill drive[1] 847 hp (632 kW) ​  • Rating 1 hour 760A[3]  • Continuous 700A[3] Gear ratio 29:76 (Type A) 26:83 (Type B)[1] Train heating Electric Train Heating Loco brake Westinghouse[1] Air, Rheostatic Train brakes Vacuum; Dual from 1972–1973
Performance figures Maximum speed 100 mph (161 km/h) Full field: 60 mph (97 km/h) Weak field: 71 mph (114 km/h)[1] Power output: ​  • 1 hour 4 × 920 hp (690 kW)[3]  • Continuous 4 × 847 hp (632 kW)[3] Tractive effort 50,000 lbf (222 kN)
Career Operators British Rail Numbers E3001–E3023, E3096, E3097; later 81001–81022 Axle load class Route availability 6 Retired 1968 (2), 1971 (1), 1983–1991 Preserved 81002 Disposition 1 preserved, remainder scrapped

The British Rail Class 81 is a class of AC electric locomotives that formerly operated on the West Coast Main Line of the London Midland Region of British Rail. Originally designated AL1, it was the first type of AC electric locomotive to be delivered to British Railways.