LNER Thompson Class L1
No. 67781 at Neasden Shed 1957
|Type and origin|
|Build date||1945, 1948–1950|
|UIC classification||1′C2′ h2t|
|Gauge||4 ft 8 1⁄2 in (1,435 mm)|
|3 ft 2 in (0.965 m)|
|Driver diameter||5 ft 2 in (1.575 m)|
|3 ft 2 in (0.965 m)|
|Length||43 ft 4 in (13.21 m)|
|Axle load||20.00 long tons (20.32 t)|
|Weight on drivers||58.95 long tons (59.90 t)|
|Locomotive weight||89.45 long tons (90.89 t)|
|Fuel capacity||4.50 long tons (4.57 t)|
|Water capacity||2,630 imp gal (12,000 l; 3,160 US gal)|
|Boiler||LNER diagram 115|
|Boiler pressure||225 lbf/in2 (1.55 MPa)|
|Firegrate area||24.75 sq ft (2.299 m2)|
|830.0 sq ft (77.11 m2)|
|– Flues||368.0 sq ft (34.19 m2)|
|– Firebox||138.5 sq ft (12.87 m2)|
|– Total||1,336.5 sq ft (124.16 m2)|
|Superheater area||284.0 sq ft (26.38 m2)|
|Cylinder size||20 in × 26 in (508 mm × 660 mm)|
|Valve type||10-inch (254 mm) piston valves|
|Tractive effort||32,080 lbf (142.70 kN)|
|Power class||BR: 4MT|
|Axle load class||Route Availability 7|
The London and North Eastern Railway (LNER) Thompson Class L1 was a class of 2-6-4T steam locomotives designed by Edward Thompson. The prototype no. 9000 was built in 1945, but the remaining 99 were built under British Railways jurisdiction in the period 1948–1950.
The class, at least on paper, should have been very free steaming and powerful engines but, in practice, they were not suited to the work to which they were assigned. The engines had 5-foot-2-inch (1.575 m) driving wheels, which would give them excellent power at low speed, such as that required for freight work, but these engines were intended for passenger use. The speeds required for suburban passenger work wore the engines out in a remarkably short time. Axleboxes, crosshead slides and crank bearings all suffered due to the high speeds.
Accidents and incidents
- On 19 November 1958, a freight train overran signals and was in a rear-end collision with another at Hitchin, Hertfordshire. A third freight train ran into the wreckage and was derailed. Locomotive No. 67785 was pushed over by the wagons from the third train.
In an attempt to reduce wear, two experiments were tried. In May 1951, five locomotives had liners fitted to their cylinders to reduce the cylinder bore from 20 to 18 3⁄4 in (508 to 476 mm). In March 1953, five locomotives had their boiler pressure reduced from 225 to 200 lbf/in2 (1.55 to 1.38 MPa). Neither experiment was a success.
|Build date||Builder||Serial number||LNER number||Original BR number||New BR number|
|1945||LNER Doncaster Works||1984||9000||69000||67701|
|1948||BR Darlington Works||2020–2034||9001–9003, E9004–E9012||69001-69015||67702-67716|
|1948||BR Darlington Works||2035–2048||—||–||67717-67730|
|1948–1949||North British Locomotive Company||26570–26604||—||—||67731-67765|
|1949–1950||Robert Stephenson and Hawthorns||7500–7534||—||—||67766-67800|
Withdrawals were between 1960 and 1962. None survived to preservation.
|Wikimedia Commons has media related to LNER Thompson Class L1.|
- Boddy et al. 1977, p. 16, 29–31.
- Trevena, Arthur (1981). Trains in Trouble: Vol. 2. Redruth: Atlantic Books. pp. 40–41. ISBN 0-906899 03 6.
- Boddy et al. 1977, p. 16.
- Boddy, M. G.; Brown, W. A.; Fry, E. V.; Hennigan, W.; Hoole, Ken; Manners, F.; Neve, E.; Platt, E. N. T.; Proud, P.; Yeadon, W. B. (March 1977). Fry, E. V., ed. Locomotives of the L.N.E.R., Part 9A: Tank Engines—Classes L1 to N19. Kenilworth: RCTS. ISBN 0-901115-40-1.