LNWR G Class

Infobox Locomotive
powertype=Steam
name = LNWR G Class


caption = The preserved G2a class No. 49395, 2 October 2005. It is part of the National Railway Collection.
designer = Charles Bowen-Cooke
builder =
builddate = 1879
totalproduction =
whytetype = 0-8-0
gauge =
leadingsize =
driversize =
length =
weight = 60 tons 15 cwt
fueltype = coal
fuelc

waterc

cylindercount = 2
cylindersize = 20½"x24"
firearea =
boilerpressure = 160 psi
tractiveeffort = 25,640 lb
railroadclass=6F/7F| The London and North Western Railway (LNWR) G Class along with modifications that made them into G1, G2 and G2a classes, is a class of 0-8-0 steam locomotives designed for heavy freight work. They are known to railway enthusiasts as "Super Ds". This is because a large number of G1 class engines were rebuilt from George Whale class D 0-8-0s. They were Super Ds - super for superheated. The D class existed as such between 1906 and 1937. All this is explained by Willie Yeadon's book [Willie Yeadon "A Compendium of LNWR Locomotives 1912-1964 Part Two Goods Tender Engines," Challenger Publications, April 1996, p69.] .

Overview

The LNWR built eight-coupled locomotives under Webb, Whale, Bowen-Cooke and Beames between 1892 and 1922. The G class were originally introduced in 1906 as modifications of the 4-cylinder compound B Class 0-8-0s by removing their outside cylinders to give a simpler two cylinder layout. From 1912 superheating was introduced and most of the B class were converted into G1 Class, not G Class. The G2 class were new builds with increased boiler pressure from 160lbf/in² to 175psi. Some G1s were converted to G2a classes after their boiler pressure was increased.

After grouping in 1923, they were acquired by the LMS who gave them the power classifications 6F for G1 and 7F for G2 and G2a locomotives. The design of the LMS 7F 0-8-0 (known as the "Austin 7") was derived from the G2 but the former was a poor engine in comparison and the "Super Ds" outlived the "Austin 7s".

Many of the G1, G2 and G2a Class locomotives passed into British Railways (BR) ownership in 1948 and were numbered as follows:

* G1 Class, (98 locos), BR numbers 48892-49384
* G2 Class, (60 locos), BR numbers 49395-49454
* G2a Class, (320 locos), BR numbers 48893-49394

The final four engines in traffic were 48895, 49361, 49407 and 49430. They were withdrawn in December 1964. It is interesting to note that at least two of these engines, 49361 and 49430, were allocated to Northampton shed (2E). There was a farewell railtour 12th December 1964. ["Railway Magazine" March 1965 p179.] The G1 and G2a numbers are intermingled (probably because the G2a is a rebuild of the G1) and there are some gaps in numbering. [cite book|title=Ian Allan ABC of British Railways Locomotives, part 3|date=1948|pages=pp 30-40]

Preservation

One G2a, LMS 9395, BR number 49395, has survived as part of the National Railway Collection and has been returned to working order thanks to a lot of money from Pete Waterman. [cite journal|author=Smith, Ian R.|title=The wheezing 'Super D'|journal=Heritage Railway|volume=3|date=July 1999|pages=66–7]

Dimensions

G1 Class

* LMS/BR Power classification, 6F
* Locomotive weight, 60 tons 15 cwt
** Tender weight, Not known
* Boiler pressure, 160 psi
* Superheater, Yes
* Cylinders, 20½"x24"
* Driving wheel diameter, 4' 5½"
* Tractive effort, 25,640 lb
* Valve gear, Joy (piston valves)

G2 and G2a Classes

* LMS/BR Power classification, 7F
* Locomotive weight, 62 tons 0 cwt
** Tender weight, Not known
* Boiler pressure, 175 psi
* Superheater, Yes
* Cylinders, 20½"x24"
* Driving wheel diameter, 4' 5½"
* Tractive effort, 28,045 lb
* Valve gear, Joy (piston valves)

For terminology, see Steam locomotive components

Models

As of 2008, Bachmann produce a 00 Gauge/4mm model of the G2A, availible in LMS and BR Liveries.

References

External links

* [http://www.lnwrs.org.uk/GoodsLocos/Loco16.php Goods Engines of the LNWR G Class]
* [http://www.railuk.co.uk/steam/getsteamclass.php?item=G1 Rail UK database G1 Class]
* [http://www.railuk.co.uk/steam/getsteamclass.php?item=G2 Rail UK database G2 Class]
* [http://www.railuk.co.uk/steam/getsteamclass.php?item=G2A Rail UK database G2a Class]