GWR 4900 Class

Infobox Locomotive
powertype=Steam
name = GWR 4900 Class


caption = Preserved 4936 "Kinlet Hall"
designer = Collett
builder = GWR
builddate = 1928
totalproduction =
whytetype = 4-6-0
gauge = 4' 8½"
leadingsize =
driversize = 6' 0"
length =
weight = 75 tons 0 cwt
fueltype = coal
fuelc

waterc

cylindercount = two outside
cylindersize = 18½" x 30"
firearea =
boilerpressure = 225 psi
tractiveeffort = 27,275 lbf
railroadclass= 5MT|

The Great Western Railway 4900 Class or Hall Class is a class of 4-6-0 mixed traffic steam locomotives designed by Charles Collett. A total of 259 were built, numbered 4900–99, 5900–99 and 6900–58. The LMS Stanier Class 5 4-6-0 and LNER Thompson Class B1 both drew heavily on design features of the Hall Class. After nationalisation in 1948, British Railways gave them the power classification 5MT.

Overview

Prototype

The prototype was rebuilt from GWR Saint Class no.2925 "Saint Martin" in 1924 with smaller driving wheels. Additionally the cylinders were realigned in relation to the driving axle and a more modern 'Castle'-type cab was fitted. The rebuilt "Saint Martin" emerged from Swindon in 1924 and, renumbered 4900, embarked on three years of trials. During this period Collett introduced other modifications. The pitch of the taper boiler was altered and outside steam pipes were added.

Production

Satisfied with no.4900's performance Collett placed an order with Swindon works and the first of the new two-cylinder Halls entered service in 1928. They differed little from the prototype; the bogie wheel diameter had been reduced by two inches from 3ft 2in to 3ft 0in and the valve setting amended to give an increased travel of 7 1/2in. The overall weight of the locomotive had increased by 2 1/2 tons to 75 tons but a tractive effort of 27,275lb compared favourably with the 24,935lb of the 'Saint'.

In what amounted to a trial run the first 14 were despatched to the arduous proving grounds of the Cornish main line. However they were so successful here and elsewhere on the GW system that by the time the first production batch of 80 had been completed in 1930 a further 178 were on order. By 1935 150 were in service and the 259th and last Hall, no.6958 "Oxburgh Hall", was delivered in 1943.

Modified Hall

Collett had been replaced by F.W. Hawksworth in 1941 and Hawksworth created a modified version known as the Modified Hall Class which remained in production until 1950. One of Hawksworth's modifications in changing the design was to equip it better to cope with the low quality coal available during the war. If anything the situation worsened after the war, leading to serious consideration being given to oil firing. Beginning in 1946 with no.5955 "Garth Hall" the GWR converted 11 of the class to burn oil. Within four years, however, they had all reverted to coal.

British Railways

All but one of the original Collett Halls entered British Railways service in 1948, the exception being no.4911 "Bowden Hall" which took a direct hit during a bombing raid on the Plymouth area in April 1941 and was broken up. Official withdrawals began in 1959 with the prototype "Saint Martin". Its accumulated mileage, both in its original form and rebuilt form, was a remarkable 2,092,500 miles.

Preservation

By 1965 the last Hall had been withdrawn from the Western Region without a single one entering the National Collection. Thankfully 11 Halls have survived to preservation and No. 4942 "Maindy Hall" is being back-converted into a GWR Saint Class locomotive at Didcot Railway Centre.

List of locomotives

*List of GWR 4900 Class locomotives

In fiction

In the Harry Potter films, No. 5972 Olton Hall is used to pull the Hogwarts Express.

References

Collett & Hawksworth Locomotives—A Pictorial History, Brian Haresnape, Ian Allen Ltd, 1978, ISBN 0-7110-0869-8

External links

* [http://www.greatwestern.org.uk/m_in_hal.htm Great Western archives - Hall class]
* [http://www.4930hagleyhall.co.uk Friends of Locomotive 4930 Hagley Hall]