The Q6s were an unqualified success. By combining Worsdell's motion with the B15 boiler and the Schmidt superheater, Raven managed to create a strong and reliable locomotive which gave good strong service right up to the end of BR steam.
Due to their success, the Q6s experienced very modifications during their lives. From 1930, the Schmidt superheaters were replaced with Robinson superheaters to bring them in line with LNER practice. From 1938, the boiler design was updated from Diagram 50 to Diagram 50A. The 50A boilers had their domes 1ft 3in further back, and a sloping firebox throatplate was fitted. The boiler tubes were also increased from 144 to 156.
The Q6s had no train-braking ability, but they did have a single brake cylinder which operated the brakes on the tender and locomotive. On one occasion in 1942, the operating link failed causing a run-away from Morrison's Colliery into South Pelaw Junction. This only happened once and the Board of Trade's inspector was satisfied with the testing arrangements for the links. The lack of train-braking ability meant that the Q6s could not pull passenger trains except under unusual circumstances. One of these was in 1936 when a Q6 from Selby hauled a failed D20 into Leeds. The D20 braked the train and provided carriage heating whilst the Q6 provided the hauling power.
General withdrawals started in 1963, and the last Q6 was withdrawn in 1967.
Technical Details
Cylinders (x2): | 20x26in. | |
Motion: | Stephenson | 8.75in piston valves |
Boiler: | Max. Diameter: | 5ft 6in |
Pressure: | 180psi | |
Diagram No.: | 50 | |
Heating Surface: | Total: | 1730 sq.ft. |
Firebox: | 140 sq.ft. | |
Tubes: | 723 sq.ft. (90x 2in) | |
Flues: | 506 sq.ft. (24x 5.25in) | |
Superheater: | 361 sq.ft. (24x 1.1in) | |
Grate Area: | 23 sq.ft. | |
Wheels: | Coupled: | 4ft 7.25in |
Tractive Effort: | 28,800lb | (@ 85% boiler pressure) |
Wheelbase: | Total: | 42ft 7.75in |
Engine: | 17ft 2in | |
Tender: | 12ft 8in | |
Weight (full): | Total: | 110 tons 0cwt |
Engine: | 65 tons 18cwt | |
Tender: | 44 tons 2cwt | |
Max. Axle Load: | 17 tons 12cwt |
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