Great Northern / Great Northern/LNER 2-8-0 Locomotives in Great_Britain

Class O2 - 461 (Locobase 20682)

Data from "New Three-Cylinder 2-8-0 Locomotive for Mineral Traffic", Great Northern Railway", Locomotive Magazine, Volume XXIV [24], No 310 (15 June 1918), pp. 93-94; and "Valve Gear for Three-Cylinder Mineral Engine No 461, GNR", LM, Volume XXIV, No 314 (15 October 1918). Additional information from Richard Marsden's LNER Encyclopedia -- [], visited 26 September 2004; and Bryan Attewell ([] Steam locomotive simulator (April 2000 edition). .

Nigel Gresley's trial horse #461 appeared in May 1918 and aroused considerable interest because of its size and the use of his valve gear. Marsden notes that much of the design was based on the O1 (Locobase 3124), including the boiler and the double-swing-link suspension used in the pony truck.

461 used pendulum rocking shafts to actuate vertical levers inside. LM's 15 October 1918 report gives full details and diagrams showing the layout. Simply described, the right-side outside cylinder's valve moved back and forth in a standard radial valve gear pattern. But the valve rod also moved a horizontal arm that pivoted on a fulcrum set inside at two-thirds of its total length.

The leftmost third of the large arm ended with a fulcrum that. Pivoting on this boss was a smaller lever equally distant from inside (center valve and cylinder) and the left-side outside cylinder. Its ends accepted the ends of the piston rods to those two valves.

To allow all three cylinders to drive the second axle, Gresley mounted the outside cylinders at a 1 in 8 incline. As can be seen in Locobase 3215, the production variant that appeared three years later repeated many of the features of the 461. But the lever-system was replaced by Gresley's conjugated valve gear.

461 served the GN and the LNER along with the other O2s well into the 1950s.,

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Class O2 - 477 (Locobase 3125)

Data from "New Three-Cylinder 2 LocomotivE,, Great Northern Railway", Locomotive Magazine, Volume XXVII [27], No 346 (15 June 1921), pp. 137-138. Additional information from Richard Marsden's LNER Encyclopedia -- [], visited 26 September 2004; and Bryan Attewell ([] Steam locomotive simulator (April 2000 edition). .

The Great Northern's trial horse #461 appeared in May 1918 (Locobase 20682) and used rocking shafts instead of motion levers, but Gresley redesigned the front end to use the Gresley-Holcroft 2-1 conjugating gear (described in detail in Locobase 2417) to actuate the three 8" (203 mm) piston valves. The new design was easier to maintain. This change appeared on the North British Locomotive Company batch of 10 that were ordered in March 1919 and delivered in 1921. At the time, the GN stated that the new engines would haul 1,300 ton (1,430 short ton) mineral trains from Peterborough to London.

Other differences from the 461 included seven fewer small tubes for slightly reduced heating surface area and a 10-psi (0.93 bar) increase in boiler pressure. Although adhesion weight grew by 15 cwt (1,680 lb or 762 kg), tweaks in other design elements led to engine weight dropping by 12 cwt (1,344 lb or 610 kg). A new Gresley leading truck pivoted on a transverse stay plate, using "top and bottom bolsters carried by inclined swing links." The layout caused each set of links to incline" in a direction opposite to the other", counteracting any tendency of a front wheel to lift when traversing a curve.

Two years later, 15 more appeared that were trimmed to fit the Grouped lines' Composite Loading Gauge height limit of 13 ft 1/2 inch (3.97 m). These had split-ring piston valves that had to be replaced by the Knoorr type because of lubrication and wear problems, says Marsden.

Accepted as the Group Standard Consolidation, the O2/3 was produced in small batched over the next 20 years. Eight were ordered in 1929 (delivered in 1932). Long-travel valves were adopted for all three-cylinder designs in 1930 and these were fitted to the 8 ordered in 1933 and the 25 produced in 1942-1943 to meet wartime traffic demands. Four more were completed with the same boiler as the one used in the Thompson B1 4-6-0s, but cut to a shorter length and pressed to 180 psi.

Used widely on the LNER, this powerful class of Consolidations was taken into British Railways in 1948, although the first retirement (3921, the renumbered 461) followed shortly thereafter. The rest didn't begin retirement until 1960 and the last 40 were withdrawn in 1963.

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Class Tangos / O1 (Locobase 3657)

Data from "Consolidation Engine for Mineral Traffic, Great Northern Ry", Locomotive Magazine, Volume XX [20], No 257 (15 January 1914), pp. 1-2. See also

"O-1 class" from Steamindex.com at [], last accessed 207 November 2017; and "The Gresley O1 (later O3) 2-8-0 Locomotives" from Richard Marsden's LNER Encyclopedia at [], last accessed 27 November 2017.

Designed by Nigel Gresley for the mineral (e.g. coal) trains in the early days of his superintendency. They were rated at 80 wagons aggregating a trailing load of 1,300 tons (up from 975 tons in 60 wagons) and running between Peterborough and the GN's Ferme Park yard in London.

Thus it was a two-cylinder engine with outside cylinders sporting the largest dimensions of any Doncaster-built locomotive and 10" (254 mm) piston v alves, but possessing a healthy degree of superheat. As originally built, the superheater was credited with 570 sq ft (52.95 sq m).

North British Locomotive Company built fifteen more in 1921, A further fifteen locomotives were constructed by the North British Locomotive Co. in 1919 that used a piston valve developed by the Canadian Pacific Railway and first tested on engine 460. But all of these valves were replaced in 1922 with a design featuring, says steamindex's summary,"a single split ring with tiny holes in its circumference to admit lubricated steam to the surface of the ring to overcome friction when starting." Marsden reports that "the problem was solved by fitting Great Eastern (GER) pattern Knorr-type piston valves to the O1s from 1924."

Marsden's service history underscores the O1's role as a heavy hauler at modest speeds on difficult profiles.