The reference for locomotives and railcars


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Great Western Railway class 4500 “Small Prairie”
Great Britain | 1906 | 75 produced
No. 4566 in use on the Severn Valley Railway in 2011, retired in 2017
No. 4566 in use on the Severn Valley Railway in 2011, retired in 2017
Hugh Llewelyn

Analogous to the “Large Prairies”, Churchward had a smaller engine built in 1905, which was given the number 115 and founded the “Small Prairies” family. With a driving wheel diameter of four feet and 1.5 inches, smaller cylinders and a smaller boiler, it was designed for use with passenger and goods trains on branch lines. The ten other production engines were initially given the numbers 3101 to 3110 and became the class 4400 with the new designation scheme of 1912. Since they were only suitable for shorter distances with the small wheel diameter, further locomotives with a driving wheel diameter of four feet and 7.5 inches were built since 1906.

By 1912, initially 30 engines with the numbers 2161 to 2190 had been produced. In 1912 they were re-designated class 4500, under which they are better known. Another 25 engines were made by 1915 and finally the last 20 engines in 1924. Although they could be used more widely than the Class 4400 thanks due to their larger wheels, they were primarily used on the hilly branch lines of the GWR in South Wales and Devon. Three were loaned to the Rhondda and Swansea Bay Railway, which was taken over by the GWR in 1922. The last engines were retired in 1963 and three were preserved, with one operational in 2020, one being refurbished and the third on display at the Severn Valley Railway.

Axle config2-6-2T (Prairie) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Wheelbase31 ft 9 in
Fixed wheelbase14 ft 9 in
Empty weight127,674 lbs
Service weight139,328 lbs
Adhesive weight107,400 lbs
Water capacity1,201 us gal
Fuel capacity6,720 lbs (coal)
Power sourcesteam
Estimated power850 hp (634 kW)
Optimal speed26 mph
Starting effort21,245 lbf
Power Plant
Driver diameter55.5 in
Boiler pressure200 psi
Expansion typesimple
Cylinderstwo, 17 x 24 in
Grate area16.6 sq ft
Firebox area94.3 sq ft
Tube heating area992.8 sq ft
Evaporative heating area1,087 sq ft
Superheater area77 sq ft
Total heating area1,164 sq ft
Calculated Values
steam locomotive
tank locomotive
George Jackson Churchward
last changed: 02/2022

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