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Locomotive Facts & Figures

Technical Details

The following details are for No. 3401, and also apply for No. 3402 after May 1945.

ITEM Imperial Metric
Cylinders (x3):   15x26in.
Motion: Outside: Walschaerts
  Inside: Gresley
  Valves: 7in piston
Boiler: Max. Diameter 5ft 4in
  Pressure: 250psi
  Diagram No.: 112
Heating Surface Total: 1799.9 sq.ft.
  Firebox: 151.6 sq.ft.
  Superheater: 355.8 sq ft
  Tubes: 884.3 sq.ft. (143x 1.75in dia.)
  Flues: 408.2 sq.ft. (22x 5.25in dia.)
Grate Area:   28.5 sq.ft.
Wheels: Leading: 3ft 2in
  Coupled: 5ft 8in
  Trailing: 3ft 2in
Tractive Effort: (@ 85%) 27,420lb
Wheelbase: Total: 50ft 2.25in
  Engine: 29ft 4in
  Tender: 13ft
Weight: (full) Total: 113 tons 3cwt
  Engine: 70 tons 8cwt
  Tender: 42 tons 15cwt
Max. Axle Load:   17 tons