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Midland Railway 1000 Class
Type and origin
Power type Steam
Designer Samuel Waite Johnson: renewed as superheated Deeley compound by Henry Fowler
Builder Derby Works
Build date 1902–1909
Total produced 45
Rebuild date 1913–1928
UIC classification2′B h3v
Gauge 4 ft 8 1⁄2 in (1,435 mm)
Leading wheel diameter3 ft 6 1⁄2 in (1.080 m)
Driver diameter7 ft 0 in (2.134 m)
Fuel type Coal
Boiler 2631–2635 and 1000–1004: G8½
All rebuilt with G9AS
Boiler pressure 220 psi (1.52 MPa)
Cylinders Three, one inside high-pressure, two outside low-pressure
High-pressure cylinder size19 in × 26 in (483 mm × 660 mm)
Low-pressure cylinder size21 in × 26 in (533 mm × 660 mm)
Valve gear Stephenson
Valve type HP: piston valve, LP: slide valves
Tractive effort 21,840 lbf (97.1 kN)
Operator MR → LMS → BR
Power class 4P
Disposition One preserved, remainder scrapped.
These were developed from a series of five locomotives (2631–2635), introduced in 1902 by Samuel W. Johnson, which had had a 3-cylinder compound arrangement on the Smith system. This had a layout of one high pressure cylinder inside the frames, and two low pressure cylinders outside, and utilised Smith's starting arrangement. On the first two locomotives, independent control of high-pressure and low-pressure valve gears was available. From 1905 onwards, Johnson's successor Richard Deeley built an enlarged and simplified version, eliminating all the Smith refinements whilst fitting his own starting arrangement, making the engines simpler to drive. These locomotives were originally numbered 1000–1029, but in the 1907 renumbering scheme the five Smith/Johnson locomotives became 1000–1004 and the Deeley compounds 1005–1034, ten more of these being added in 1908–1909. The original Johnson locomotives were all subsequently renewed as Deeley compounds, including the now-preserved 1000 which was rebuilt and outshopped with a superheater in 1914.
Numbered 1000–1044 by both the Midland and LMS companies, British Railways renumbered the Midland series of compounds 41000–41044 after nationalisation in 1948.