London, Midland & Scottish Coronation class
For a new non-stop train between London and Glasgow, the LMS commissioned a new Pacific in the mid-1930s, which was supposed to be stronger, more reliable and easier to maintain than the Princess Royal. The train was called “Coronation Scot” and the locomotive “Coronation class”. The ten locomotives from the first batch and ten more from a later batch were built streamlined. This was apparently not planned at the beginning, but was subsequently decided due to the public appeal of the competing LNER A4.
No. 6220 “Coronation” achieved a British record of 114 mph (183 km/h) in 1937, which only lasted one year. Another record was also broken in 1939 with 2,511 hp on the drawbar, which still stands today for British steam locomotives. The streamlined paneling was removed from all locomotives by 1948 because the advantages over the much more complicated maintenance were limited. Most were scrapped between 1962 and 1964 after they were replaced by electric locomotives and no further use could be found. No. 6233 “Duchess of Sutherland” is the only one of the three surviving that was operational in 2023, but was withdrawn without further notice.
Technical data
General
- Built
- 1937-1948
- Manufacturers
- Crewe
- Wheel arrangement
- 4-6-2 (Pacific)
- Gauge
- 1,435 mm (Standard gauge)
Dimensions and weights
- Wheelbase
- 11.28 m
- Total wheelbase
- 19.18 m
- Service mass
- 108.1 t
- Adhesion mass
- 68.2 t
- Total mass
- 166 t
- Rigid wheelbase
- 4.42 m
- Axle load
- 22.9 t
- Water capacity
- 18,185 l
- Fuel capacity
- 10.2 t (coal)
Boiler
- Grate area
- 4.645 m²
- Firebox surface
- 21.414 m²
- Tube heating surface
- 258.735 m²
- Evaporative heating surface
- 280.149 m²
- Superheater surface
- 79.153 m²
- Total heating surface
- 359.3 m²
Power plant
- Driver diameter
- 2,057 mm
- Boiler pressure
- 17.2 bar
- Expansion type
- simple expansion
- Cylinders
- four, 419 x 711 mm
Power
- Power source
- steam
- Estimated power
- 2,461 kW (3,346 PS)
- Starting effort
- 177.9 kN
Calculated values
- Factor of adhesion
- 1 : 3.76
- Optimal speed
- 85 km/h
- Power-to-weight ratio
- 22.8 kW/t
- Heating Surface Equivalent
- 545.5 m²
- Cylinder volume/HSE
- 1 : 719.39
- Adhesive weight/Total
- 1 : 1.59
- Tractive force/Heating surface
- 1 : 10.34
- Grate area/Heating surface
- 1 : 77.35
- Firebox/Tube surface
- 1 : 12.08
- Total/Superheater
- 1 : 3.54