The Robinson Q4 (GCR Class 8A) 0-8-0 Locomotives
The Great Central Railway (GCR) Class 8A (LNER Q4) was designed by Robinson in 1902. The first three locomotives were built alongside the first GCR Class 8 (LNER B5) locomotives and they shared similar 4ft 9in diameter saturated boilers. The main difference was that the Q4's smaller wheels enabled a deeper firebox to be used.
Superheaters were first fitted in 1914. The fitting of superheaters would continue into LNER ownership although eight Q4s would remain saturated for their entire lives.
At Grouping, the Q4s were split into the Q4/1 and Q4/2 classifications according to the type of tender in use. In December 1924, they were reclassified according to whether they were above 13ft 1in in height. Another reclassification in December 1928 described both the height and tender variations in four classifications (Q4/1, Q4/2, Q4/3, and Q4/4). From December 1943, a final reclassification indicated saturated and superheated boilers as Q4/1 and Q4/2 respectively.
The "Tinies" as they were quickly nicknamed, were initially put to work hauling the GCR's coal traffic with a large number allocated to Mexborough. Large purchases of ex-ROD O4 2-8-0 locomotives by the LNER led to the displacement of the Q4s to the Great Northern (GNR) district and to the West Riding. During the 1930s, many of the Q4s replaced the Q1/Q2/Q3 "Long Toms" which were being withdrawn from West Riding freight services. The Q4s were ideally suited for these services because the more powerful O4 2-8-0s were too large for the Ardsley turntable. When the turntable was finally replaced in 1936, the Q4s remained popular with engine crews mainly due to their improvement over the old Q1/Q2/Q3 "Long Toms".
Withdrawals started in 1934, and by 1938 it had been decided to completely eliminate the class. With a shortage of heavy freight locomotives during World War 2, the withdrawal process was stopped in early 1940 although another engine was withdrawn in 1943. Of the remaining forty Q4 locomotives, Thompson rebuilt thirteen as Q1 0-8-0T tank engines. Rebuilding of all of the remaining Q4s was authorised, but was halted in 1945. As with the ex-ROD O4 2-8-0 locomotives at the end of World War 1, the LNER purchased large numbers of ex-WD O7 2-8-0 locomotives at the end of World War 2. These quickly made the Q4s redundant, and the last Q4 was withdrawn in 1951.
The following details are for the Q4s with slide valves and the 21-element superheater at the time of Grouping (1923). Superheaters continued to be fitted during LNER ownership, although not all were converted. No. 1134 was fitted with a small-tube superheater of area 657 sq.ft. but this was converted to use the standard 21-element superheater in 1924.
|Boiler:||Max. Diameter:||4ft 9in|
|Heating Surface:||Total:||1568 sq.ft.|
|Tubes:||756 sq.ft. (94x 2in)|
|Flues:||442 sq.ft. (21x 5.25in)|
|Grate Area:||23.62 sq.ft.|
|Tractive Effort:||25,644 lb||(@ 85% boiler pressure)|
|Weight (full):||Total:||107 tons 3cwt|
|Engine:||63 tons 0cwt|
|Tender:||44 tons 3cwt|
|Max. Axle Load:||17 tons|
The last Q4 was withdrawn in 1951 and none survived into preservation.
Millholme have produced a whitemetal kit of the Q4 for OO gauge (4mm scale), but this is no longer available.
Gladiator sell a kit of the Q4 for 7mm scale (O gauge).