LNER Thompson Class L1

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LNER Thompson Class L1[1]
Neasden loco shed geograph-2361104-by-Ben-Brooksbank.jpg
No. 67781 at Neasden Shed 1957
Type and origin
Power type Steam
Designer Edward Thompson
Build date 1945, 1948–1950
Total produced 100
Configuration 2-6-4T
UIC class 1′C2′ h2t
Gauge 4 ft 8 12 in (1,435 mm)
Leading dia. 3 ft 2 in (0.965 m)
Driver dia. 5 ft 2 in (1.575 m)
Trailing dia. 3 ft 2 in (0.965 m)
Length 43 ft 4 in (13.21 m)
Axle load 20.00 long tons (20.32 t)
Adhesive weight 58.95 long tons (59.90 t)
Loco weight 89.45 long tons (90.89 t)
Fuel type Coal
Fuel capacity 4.50 long tons (4.57 t)
Water cap 2,630 imp gal (12,000 l; 3,160 US gal)
 • Firegrate area
24.75 sq ft (2.299 m2)
Boiler LNER diagram 115
Boiler pressure 225 lbf/in2 (1.55 MPa)
Heating surface 1,336.5 sq ft (124.16 m2)
 • Tubes 830.0 sq ft (77.11 m2)
 • Flues 368.0 sq ft (34.19 m2)
 • Firebox 138.5 sq ft (12.87 m2)
 • Heating area 284.0 sq ft (26.38 m2)
Cylinders Two, outside
Cylinder size 20 in × 26 in (508 mm × 660 mm)
Valve gear Walschaerts
Valve type 10-inch (254 mm) piston valves
Performance figures
Tractive effort 32,080 lbf (142.70 kN)
Class L1
Power class BR: 4MT
Numbers BR: 67701–67800
Axle load class Route Availability 7
Withdrawn 1960–1962
Disposition All scrapped

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[edit]

  • 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.[2]


In an attempt to reduce wear, two experiments were tried.[3] In May 1951, five locomotives had liners fitted to their cylinders to reduce the cylinder bore from 20 to 18 34 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.


Sources [4][5][6] were used to compile the following table:

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.


Hornby produces the L1 class in 00 gauge with a number of different liveries, both green with LNER or BR running numbers,[7][8] and black with BR running numbers.[9][10]


  • 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.