GWR 3100 Class

Infobox Locomotive
powertype=Steam
name = GWR 3100 Class
(1938 rebuild of 3150 Class)


caption =
designer = Churchward
(rebuilt by Collett)
builder = GWR
builddate = 1906 (rebuilt 1938)
totalproduction = 5
whytetype = 2-6-2
gauge = 4' 8½"
leadingsize =
driversize = 5' 3"
length =
weight = 81 tons 9 cwt
fueltype = coal
fuelc

waterc

cylindercount = two outside
cylindersize = 18½" x 30"
firearea =
boilerpressure = 225 psi
tractiveeffort = 31,170 lbf
railroadclass= 4MT|

The Great Western Railway (GWR) 3100 Class was a class of 2-6-2T side tank steam locomotive. This was developed from one of George Jackson Churchward's pioneer designs; the experimental No 99. The basic design was so sound that derivatives were built until the end of the company's life in 1948 and even beyond.

No 99 was produced in 1903 and given an extended trial over the next two years. Fitted with the standard number 2 boiler running at 200 p.s.i., flat topped tanks and driving wheels of 5 feet 8 inches diameter, this was the genesis of 289 similar locos that were to follow. Thirty nine more examples were built to this initial design. This production batch differed from the prototype only in that the tank tops were sloping to aid visibility and the cab sides were incorporated into the tanks. The running numbers of this batch were 3111 to 3149 and the prototype was logically renumbered 3100.

3150 class

1906 saw the first alteration to the design of the class, when numbers 3150 to 3190 (known as the GWR 3150 Class) were produced using the larger standard number 4 boiler, again running at 200 p.s.i. These two classes were the basis of what was to follow for over forty years.

5100 and 5101 classes

A renumbering in 1927 saw the original forty renumbered 5100, and 5111 to 5149. The next additions to the class filled in the numbers 5101 to 5110 and extended the class to 5189. These locos were known as the GWR 5101 Class but were really little changed from the first batch but had an increased axle loading of 17 tons 12 hundredweight. Bunkers were of the standard Collett design with greater coal capacity. Additions to the 51xx class were made until available numbers were exhausted, and forty engines were then built in the 41xx series.

New 3100 class

In 1938 Collett rebuilt some of the oldest locos in the 31xx series with a view to using them as bankers, particularly from Severn Tunnel Junction shed. One of the two classes of rebuilds were a "new" 3100 class derived from the old 3150 class. These engines used the standard class 4 boiler again, but pressed to 225 p.s.i. and using smaller coupled wheels of 5 feet 3 inches diameter, and a half inch increase in cylinder diameter, nominal tractive effort rose to 31,170 pounds. Almost impossible to pick out was a 2" reduction in pony truck wheel diameter to 3'. Only five engines were ever modified, namely 3173, 3156, 3181, 3155 and 3179 which were rebuilt as 3100 to 3104 respectively.

ee also

* GWR 2-6-2T

External links

* [http://www.railuk.co.uk/steam/getsteamclass.php?item=3100 Rail UK database entry for "new" 3100 Class]