The Raven/Gresley A8 Pacific Tank Locomotives

Raven/Gresley A8 4-6-2T Pacific Tank

The A8s were rebuilt from Raven's H1 4-4-4T Class, by Gresley between 1931 and 1936.

During the mid-1920s, A5 4-6-2Ts were ordered for the North East Area to work alongside the H1s. It quickly became apparent that the A5s had better adhesion due to its six-coupled driving wheels. Hence in 1931, H1 No. 2162 was rebuilt as a 4-6-2T and given the A8 classification. After a series of trials throughout the North East Area, all of the remaining H1s were rebuilt as A8 4-6-2Ts between 1933 and 1936.

During the process of rebuilding, the boiler was modified to include a Robinson-type superheater rather than the original Schmidt superheater. In 1935, further modifications resulted in the A8 boiler being interchangeable with the A6, A7, A8, H1, and T1 classes.

The rebuilt A8s could easily work the heavy suburban traffic and long distance coastal trains on which they were put to work. They were also welcome replacements for the aging G5 0-4-4Ts which had been working these services. Allocations of the 45 locomotives were split between the North East / Newcastle area, the Yorkshire Coast (Whitby and Scarborough), Hull, and Leeds (Neville Hill).

Diesel railcars were rapidly introduced during the 1950s, and the A8s quickly became surplus to requirements. Withdrawals started in 1957, and the A8 was extinct by the end of 1960.

Technical Details

Cylinders (x3): 16.5x26in.
Motion: Stephenson 7.5in. piston valves
Boiler: Max. Diameter: 4ft 9in
Pressure: 175psi
Diagram No.: 63
Heating Surface: Total: 1084.6 sq.ft.
Firebox: 124 sq.ft.
Superheater: 191.134 sq.ft.
Tubes: 680 sq.ft. (131x 1.75in)
Flues: 280.6 sq.ft. (18x 5.25in)
Grate Area: 23 sq.ft.
Wheels: Leading: 3ft 1.25in
Coupled: 5ft 9in
Trailing: 3ft 9in
Tractive Effort: 22,940lb (@ 85% boiler pressure)
Total Wheelbase: 33ft 3in
Length: 42ft 6in
Engine Weight: (full) 86 tons 18cwt
Max. Axle Load: 17 tons 16cwt
Water Capacity: 2,000 gallons
Coal Capacity: 4 tons


The last A8 was withdrawn in 1960, and none survived into preservation.


Worsley Works produce kits of the A8 in both 2mm and 3mm scales.

OO gauge (4mm scale) kits are available from both DJH and Little Engines.