GWR 5101 Class

History

The 5101 Class were medium-sized tank engines used for suburban and local passenger services all over the Great Western Railway system. The class was an updated version, by Collett, of Churchward's 1903 3100/5100 Class.

The original 40 members of the 3100 class were renumbered 5100 and 5111 to 5149 in 1927. The first batches of 5101s filled in the numbers 5101 to 5110 and extended the class from 5150 to 5189. They were little changed from the Churchward locomotives as they then were, but had an increased axle loading of 17 long tons 12 cwt (39,400 lb or 17.9 t); the maximum permitted for the ‘Blue’ route availability. Bunkers were of the standard Collett design with greater coal capacity. The 5100 number series was exhausted in 1934, and further new locomotives were numbered from 4100.

Improvement

In 1938, the GWR began a modernisation programme to the earlier locomotives, rebuilding them to provide greater availability and more tractive effort. This would allow them to undertake their original mixed-traffic duties on a wider selection of routes, as well as banking. The 3100 class were to be rebuilt as the 3500 class, with Standard Class 4 boilers at 225psi replacing the original Standard Class 2 at 200psi, and using coupled wheels of 5 feet 3 inches diameter, which in combination took tractive effort up to 31,170 pounds. Only five engines were rebuilt pre the onset of World War II. The last of the large prairie locomotives constructed were 4140 to 4179, built to the last GWR design by British Railways at Swindon.

As both freight and passenger traffic on branch lines declined post-World War II with increasing volumes of private motor cars, and replacement on urban services by diesel-powered rail cars, the bulk of the class found itself allocated to various mainline support duties, mainly banking and piloting, often on the South Devon Banks on the Exeter to Plymouth Line, or around the Severn Tunnel on the South Wales Main Line.

Accidents and incidents

Preservation

A number of the class - 4110, 4115, 4121, 4144, 4150, 4156 and 4160 - ended their operational lives allocated to the major locomotive shed (88E) at Severn Tunnel Junction, undertaking piloting and banking duties through both the Severn Tunnel and the associated goods yard. Assistance was needed by all heavy trains through the Severn Tunnel, which entailed: 3.5 miles (5.6 km) of 1-in-90 down to the middle of the tunnel; then a further 3.5 miles (5.6 km) at 1-in-100 up to Pilning; a short level then 3.5 miles (5.6 km) more at 1-in-100 to Patchway. However, the pilot locomotive usually came off at Pilning.

All were withdrawn by June 1965, and subsequently sold for scrap to Woodham Brothers. Woodham's had prioritised processing for scrap the easier to handle former coal wagons over the more complex steam locomotives, giving rise to the large number of retained steam locomotives at Barry Island into the late 1970s. However, following a period of theft from the yard and BR being unable to offer any quantity of redundant wagons, rather than lay off staff, in summer 1980 Dai Woodham authorized the scrapping of two steam locomotives, BR Standard Class 9F No. 92085, and 5101 class No.4156. By August, more former steel coal wagons had been delivered to the yard, making 4156 and 92085 the last locomotives to be broken up at Barry.

The rest of the former Severn Tunnel Junction locomotives now form the bulk of the ten class members that have subsequently been bought for preservation. Eight are in various states or preservation or operation, whilst two have acted as donor locomotive for other projects:

Models

Graham Farish manufacture a model of the Large Prairie in N scale. Heljan are planning on producing a model of the large prairie in O gauge in 2017