The reference for locomotives and railcars


Page views since 2023-01-26: 241073
Great Western Railway class 6100 “Large Prairie”
Great Britain | 1931 | 70 produced
The 6106, seen here in September 2005, is not operational at Didcot
The 6106, seen here in September 2005, is not operational at Didcot
Chris Howells / 6106 at Didcot

Although the 70 examples were only built between 1931 and 1935, the class 6100 was the direct successor to the class 5101 built up to 1949. It was developed specifically for use in the London area as a replacement for the class 2221 4-4-2T tank locomotives built from 1905 onwards. In general dimensions and coupling wheel diameters, these locomotives were still the same as the 1903 class 5100 and the cylinders had the smaller 5101 cylinder diameter of 18 inches. With the boiler pressure increased to 225 psi, the starting tractive effort was increased by around 12.5 percent despite the reduced heating surface.

For use on the suburban platforms in London-Paddington, some locomotives were fitted with mechanical train stop, which opened a valve when passing a stop signal and thus triggered emergency braking. The typical area of application ranged from north-west London to Aylesbury, which corresponded to a distance of around 40 miles. Even after the founding of British Railways, the engines remained indispensable, but they soon faced strong competition in the form of the first generation of diesel railcars. Although their status fell as a result, the last examples were able to hold their ground in service until 1965.

Built1931-1933, 1935
Axle config2-6-2T (Prairie) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length41 ft 0 in
Wheelbase31 ft 9 in
Fixed wheelbase14 ft 9 in
Service weight175,728 lbs
Adhesive weight117,936 lbs
Axle load39,424 lbs
Water capacity2,402 us gal
Fuel capacity10,080 lbs (coal)
Power sourcesteam
Estimated power1,100 hp (820 kW)
Optimal speed26 mph
Starting effort27,338 lbf
Power Plant
Driver diameter68 in
Boiler pressure225 psi
Expansion typesimple
Cylinderstwo, 18 x 30 in
Grate area20.4 sq ft
Firebox area121.8 sq ft
Tube heating area1,145 sq ft
Evaporative heating area1,266.8 sq ft
Superheater area77.7 sq ft
Total heating area1,344.5 sq ft
Calculated Values
steam locomotive
tank locomotive
Charles Benjamin Collett
last changed: 02/2022

We use cookies to save the following settings:

  • selected navigation structure
  • selected language
  • preferred units
  • spelling of railway company names

If you refuse the use of cookies, the settings will only be retained for the current session and will be reset to the default values the next time you visit the site.

Display of units

Here you can set the desired unit system for the technical data.

  • Metric: Lengths in meters, weights in tonnes, and volumes in cubic meters
  • Imperial (UK): Lengths in feet/inches, weights in long tons and volumes in imperial gallons
  • Imperial (US): Lengths in feet/inches, weights in pounds, and volumes in US gallons
  • Individual: Depends on the country of origin of each locomotive
Operator names

Here you can set the display of railway company names.

  • Short: Abbreviation or short form of the name
  • Standard: commonly used name, partially translated to English
  • Complete: full name in local language