|Power Classification||7F reclassified 8F in 1953|
|Introduced||1919 – 1924|
|Weight – Loco||71t 12cwt|
|Driving Wheels||4ft 7¼ins|
|Boiler Pressure||180psi superheated|
|Cylinders||Three – 20½in x 26in|
|Valve Gear||Stephenson (piston valve)|
Raven became the Chief Mechanical Engineer of the North Eastern Railway (NER) in 1910 and he like Nigel Gresley was a convert of using three cylinders on a locomotive. Raven argued that three cylinders provided a smoother starting torque which was ideally suited to the NER heavy coal trains.
Although Raven’s Q6 (NER class T2) 0-8-0 mineral engine was proving to be very successful, the NER Locomotive Committee approved a three-cylinder mineral 0-8-0 locomotive design to be built in 1919 as NER class T3 (LNER Q7). This decision was based on the great success being enjoyed by Raven’s three-cylinder designs (class C7, class T1, and class A7), but many of the reasons for building the Q7s remain a mystery.
|Class C7 introduced by Raven in 1911|
|Class T1 introduced by Raven in 1909|
|Class A7 introduced by Raven in 1910|
Recent research has shown that it had its origins in winter 1917/1918 proposals by the Association of Railway Locomotive Engineers (ARLE) to produce a range of future national standard locomotives. Although this project in itself came to nothing the T3 was the NER’s own submission and it went ahead and built it regardless. The design is traditionally associated with Sir Vincent Raven, the NER Chief Mechanical Engineer. However, at the time he was seconded to the Ministry of Munitions and the credit should probably go to the acting CME, Arthur Stamer, and the Chief Draughtsman, George Heppell.
The construction of the NER class T3 (NER class Q7) appear to have been an exercise in determining the power which could be produced by a three-cylinder mineral locomotive of practical dimensions. There was no immediate demand for this extra power and in this respect suffered a similar situation as the P1 Mineral Mikado locomotives.
An interesting technical feature of this engine is the casting of all three cylinders and the smokebox saddle as a single unit, a technique pioneered in the mechanically very similar NER class Z 4-4-2 in 1911. (Interestingly, Darlington Works never possessed large foundry facilities and so the casting of these, originally at least, would have been contracted out, probably to Kitson & Co. of Leeds, who made a speciality of producing complex cylinder castings, and who regularly produced cylinders on a routine basis for the NER. Such castings for the similar S3 4-6-0 are known to have been produced after 1922 at Stratford Works in London).
Another feature of this design is the employment of three sets of Stephenson valve gear on the driving axle, a feature which it shares with MR compound 4-4-0 1000. These two locomotives are linked, having a common ancestor in the solitary NER three-cylinder compound 4-4-0 1619 of 1898, via the two Smith’s, ie Walter, chief draughtsman at Gateshead, c.1884-1906, and his elder son John, formerly of Gateshead, and chief draughtsman at Derby, 1900-1906.
NER practice was to initially build ten of a new locomotive type, however only five Q7s were built in 1919. This was followed by ten more in 1924, even though the LNER was busy reconditioning ex-ROD O4 2-8-0s for less than half the price. This second order is particularly odd because six of the ten were immediately sent to South Yorkshire to haul coal on the virtually level route from Gascoigne Wood to Hull docks, rather than the heavily graded colliery lines in the Tyneside area for which they would have been better suited.
The Q7 was based on a modified version of the C7 boiler with 102 tubes rather than 90. Schmidt superheaters were fitted as standard. This boiler was also used on the B16 4-6-0s, and it appears that both the Q7 and B16s were built with a view to the ARLE’s (Association of Railway Locomotive Engineers) World War 1 standardisation plans. These plans emphasised the maximum interchangeability of parts. The Q7 also used the ARLE’s proposed 4ft 8in diameter coupled wheel for standard mineral engines, in contrast with long standing NER size of 4ft 7¼in.
The firebox and grate were about 1ft longer than the Q6 (NER T2). Combined with the need to reduce the rear overhang, this resulted in a short cab with about 2ft of working space.
The second (LNER) batch had 133 tube boilers. Boiler designs were modified about this time with the addition of two longitudinal stays. This resulted in both boiler types being reduced by two tubes. By 1933 these stays were removed and the original 102 boilers were being phased out in favour of the 133 tube boilers. The standard superheater was switched from the Schmidt type to the Robinson type with the construction of new boilers at about this time.
The Q7s were originally based at Blaydon, Gateshead, Tyne Dock, and Hull Dairycoates. By the mid-1920s, Dairycoates found the Q6 met their needs, and their Q7 allocation was moved up to Tyne Docks. From Tyne Dock they worked the iron ore trains to Consett which involved steep gradients (some 1 in 35) and sharp bends.
|LNER class Q6 Raven two-cylinder engine introduced in 1913. This was the NER class T2|
|LNER class Q7 Raven three-cylinder engine introduced in 1919.This was the NER class T3|
The first locomotive (NER 901) of the class which was built in September 1919 it was put on dynamometer car trails at first in the Tyne Valley between Newcastle and Carlisle and later between Newport and Shildon. The train on the run to Carlisle was made up of 60 loaded coal wagoms and the dynnamoter car which gave a total train weight of 1,402 tons which 901 handled the load with ease. On the return leg with a reduced load of 787 tons the locomotive was untroubled by gradients as severe as 1 in 107.
The most notable trail with a T3 was when. 903 was tried on Glefarg bank between Perth and Edinburgh hauling a load of 755 tons made up of 30 loaded wagons and two 20 ton brake vans up the 1 in 75 bank. They performed favourably when pitted against a NBR class J37 and a GWR class 2800.
|Class Q7 Raven three-cylinder engine introduced in 1919|
|Class J37 introduced by Reid on the NBR in 1914|
|GWR class 2800 introduced by Churchward in 1903|
In normal service the T3s where allowed to take loads 20% above those of the T1 and T2s and it was actually said that the engine’s where too powerful for the traffic available and the siding accommodation. It wasn’t until they were transferred to Tyne Dock and used to work the heavy iron ore trains to Consett was there potential really reached. There are records of them being used on these trains in 1924 to haul loads of 700 tons with a second Q7 banking. The route was mainly 1 in 50, but in places reached 1 in 35 and 1 in 42. By 1949, Tyne Dock had ten diagrams operating Q7s on this route.
With the introduction of compressed air operated 56-ton bogie hopper wagons in the 1950s, five members of the class were fitted with twin Westinghouse air pumps and piping. In 1952, the Q7s would be joined by Thompson O1 2-8-0s. Between 1957 and 1959, the Westinghouse pumps fitted to the Q7s were transferred to the BR Standard 9F 2-10-0s which replaced them.
|Class Q7 Raven three-cylinder engine introduced in 1919|
|Thompson class O1 introduced in 1944 as a rebuild of the Robinson O4 class introduced in 1911|
|BR Standard 9F introduced by Riddles in 1954|
When new two of the locomotives had been allocated to York and four to Hull but during service whilst under BR ownership the fifteen locomotives were based at Tyne Dock with some having brief periods at Blaydon and Sunderland in the mid to late 1950s.
All of the Q7s were withdrawn within the two months of November and December 1962. The year 1962 witnessed the extinction of an unprecedented number of steam locomotive classes, partly for accountancy reasons with the impending elimination of the British Transport Commission on 31 December 1962, and the establishment of the British Railways Board on 1 January 1963. Also by this period the dieselisation of BR was rapidly proceeding apace with steam, still dominant in 1960, in rapid retreat. Nevertheless, all 15 T3s were fitted with AWS equipment at some cost during 1962, only months prior to their sudden withdrawal.