LNER Class K4

Infobox Locomotive
powertype=Steam
name = LNER Class K4


caption =
designer = Nigel Gresley
builder =
builddate = 1937
totalproduction =
whytetype = 2-6-0
gauge = standard gauge
leadingsize =
driversize = 5' 2"
length =
weight = 68 tons 8 cwt
tender, 44 tons 4 cwt
fueltype = coal
fuelc

waterc

cylindercount = three
cylindersize = 18½" x 26"
firearea =
boilerpressure = 200 psi
tractiveeffort = 36,600 lbf
railroadclass= 5P6F|

The London and North Eastern Railway (LNER) Class K4 is a class of 2-6-0 steam locomotives designed by Nigel Gresley for the steep grades of the West Highland Line.

Prototype

The prototype K4 No.3441 left Darlington Works for Eastfield depot in Glasgow in January 1937. After five weeks of crew training and being confined to goods work it made its début on a passenger train on the 4th of March. The steam pressure on No.3441 had been set at 180psi which resulted in a tractive effort of 32,940lb. It was soon apparent that this brought little improvement in average speeds over the existing K2 Mogul. Moreover No.3441 responded sluggishly when up against the gradients of the West Highland line. Gresley reacted by raising the steam pressure to 200psi which saw the tractive effort leap to 36,598lb. The K4 could now demonstrate its true capabilities handling 300 ton trains and with maximum speeds around 60mph on level ground. However as with all Gresley 2-6-0s it could be a rough ride at such speeds. Another advantage of the newcomer was that it used only marginally more coal in working 300 ton trains than the K2's did with considerably lighter loads.

Production

The successful trials with No.3441 led to five more being built. Apart from the prototype "Loch Long" all were named after Highland chieftains and grandees. The K4's quickly endeared themselves to the Scottish crews and, apart from some heavily loaded summer trains, eliminated uneconomic double-heading over the West Highland. The K4's retained their pre-eminence on the West Highland line until the arrival in 1947 of the first B1 4-6-0s. These were followed after nationalization by an influx of Stanier 5MT's and the new K1's that left the Gresley engines confined increasingly to goods workings.

During the 1950s the K4's sphere of operation enlarged and they began to appear at locations such as Edinburgh, Perth, Forfar, Ayr and Tweedmouth. In 1959 all were concentrated at Thornton in Junction depot in Fife and all were withdrawn in October 1961. One, 61994 "The Great Marquess", has been preserved.

Numbering

In 1945 Edward Thompson rebuilt 3445 "MacCailin Mor" into the first LNER Thompson Class K1. LNER 1946 numbers 1993-6/8 and BR numbers 61993-6/8.

Preservation

Only one of the six strong class has made it into preservation and it is the late Viscount Garnock we have to thank because on their withdrawal from service he bought No.61994 "The Great Marquess" from British Railways (BR) and had the engine overhauled to working order. Based at Leeds No.3442 undertook railtour work until forced into retirement by the ban imposed on steam working by BR in 1968. From 1972 No.3442 was stored on the Severn Valley Railway (SVR) until 1980 when it was overhauled. No.3442 has now left the SVR and has moved North back to Scotland as it runs rail tours.

ources

* Ian Allan ABC of British Railways Locomotives, summer 1961 edition, part 4, pp 33-34

External links

* [http://www.lner.info/locos/K/k4.shtml LNER encyclopedia]
* [http://www.railuk.co.uk/steam/getsteamclass.php?item=K4 Railuk database]