LNWR Webb Experiment Class

Power typeSteam

Power typeSteam

DesignerF. W. Webb

BuilderCrewe Works

LNWR Experiment Class (Webb)
No.301 Economist
Type and origin Power type Steam Designer F. W. Webb Builder Crewe Works Serial number 2500, 2625–2628, 2669–2673, 2734–2753 Build date 1882–84 Total produced 30
Specifications Configuration: ​  • Whyte 2-(2-2)-0  • UIC 1AA n3v Gauge 4 ft 8+1⁄2 in (1,435 mm) Leading dia. 3 ft 6 in (1.067 m) Driver dia. 6 ft 6 in (1.981 m) Loco weight 38 long tons (39 t) Fuel type Coal Heating surface 1,083.5 sq ft (100.66 m2) Cylinders Three: two high pressure outside, driving rear wheels; one low pressure inside, driving front drivers High-pressure cylinder 13 in × 24 in (330 mm × 610 mm) Low-pressure cylinder 26 in × 24 in (660 mm × 610 mm) Valve gear Joy valve gear for HP, and slip-eccentric valve gear for LP.
Career Operators London and North Western Railway Withdrawn 1903–1904 Scrapped 1904–1905 Disposition All scrapped

The London and North Western Railway Experiment Class was a series of 30 three-cylinder 2-(2-2)-0 compound locomotives designed by Francis Webb for the London and North Western Railway between 1882 and 1884. They were Webb’s first large-scale experiment with a class of express compound locomotives, and the first engine was named accordingly. They were followed by a class of similar, but larger locomotives, that featured larger boilers and smaller driving wheels – the LNWR Dreadnought Class.

After Webb's retirement, his successor, George Whale, withdrew the Experiment class locomotives soon after he took up office in 1903.