Heritage Railway – August 01, 2019

86 Heritagerailway.co.uk

GreatWesternRailwayStarclass4-6-0No.4003LodeStarwasdesignedby GeorgeJacksonChurchwardand

builtin1907.ROBINJONES

TheGreatWesternRailway 2800class2-8-0was

designedbyGeorg eJacksonChurchward.

Constructionoftheproductionseriescommenced

in1905 andcontinueduntil1919 .No. 2857 entered

serviceinMay1918.Vi sitingfromtheSevernValley

Railway, thelocomotive passesEskValleyonthe

NorthYorkshireMoorsRailwayonMay 24,2018.

BRIANSHARPE

thecapable S69class 4-6-0, whichbecamethe

LNER B12. Hismostlasting contributionwas

that ofstandardisation,which Gresleywisely

didnot interfere withafterthe Grouping;

leavingthe GreatEastern lines withstandard

locomotives, many of whichlastedtothe end

of steaminEastAnglia.

Superheating
At theturnofthe century, compoundingwas
beingtried by severalrailwaysand although it
resulted in economies, anothe rinvention was
found to producethe same economiesatmuch
lowercost.
In 1905 thesimplelocomotive claimed
superiorit ywiththe introduction ofWilhelm
Schmidt’s firetube superheater.Thislargely
overcamethe majorproblemofcondensation
in thecylinders of simplelocomotives and
gave an increase in poweroutputbyasmuch
as 20%.
Theintroductionofsuperheatingwas the
last but probably thesinglemostimportant
development for thesteam locomotive.
Superheating increa sesthe poweroutput
of alocomotive by as much as 25%, with
equivalent savings in coaland water,over
non-superheatedengines. Itswidespreaduse
from 1910 coincidedwiththe needsfrom
therailway operatorsfor heaviertrainstobe
hauled at higher speeds.
Thefirst design for alocomotive superheater
wasput forward in 1850.However,its use
wasnot advanced for another50years until
developmentsinmetallurgyand lubricat ing
oils capable of with standing theseverecutting
action ofhighly superheated st eam, made
superheating apractical proposition. Success
wasachievedlargely duetothe workof
Dr.WilhelmSchmidt,assis tedbyDrRobert
Garbe, chiefmechanica lengineerofthe
Berlin division ofthePrussianState Railways
andJeanBaptisteFlamme, chiefmechanical
engineerofthe BelgianRailways.
Steamgener ated in aboile risknown as
saturated ste am duetoahigh moisture
contentsince it is in contactwiththe water.
In asuperheat ed boiler this st eamispassed
throughthe regulator valveand main steam
pipetothe superheaterheaderand into
thesuperheater el ements with in thelarge

flue tubes. This superheated steamisthen

returnedtothe superheater headertobe

sent to thecylinders.The moisture that was

presentinthe saturatedsteam is turnedinto

additi onal stea mand if itstemperature is

raised high enough,the stea mapproaches

theconditi on ofaperfect gas, progressively

expandingasmoreheatisabsorbed.

Superheating becamealmostuniversal

practice on allbut shunting locomotivesand

from 1908 it wasalsofittedtocompound

locomotivesresulting in equallylarge savings.

Southern

On theLondon&SouthWestern Railway,

Drummond’s firstdesigns in the1890s were

highly su ccessful,withhis M7 0-4-4Ts and

T9 4-4 -0sproving to be some of themost

long-livedofsteam engines. Drummond

continuedtodesignuseful classes after the

turnofthe centurybut also experimented,

withvaryingdegrees of success.

He triedsuchwheel arrangements as

4-2-4T andevenbuilt aprototypeT7class

‘double sing le’4-2-2 -0 in 1897.Fivesimilar

locomotiveswerebuilt in 1901,classifiedE10.

Thelayoutwas unusualand influenced by

Francis Webb’s three-cylindercompounds

introduced in 1883 on theLNWRwithtwo

pairsofuncoupl ed drivingwheels.

As they were notcompounds,Drummond’s

aimappears to have beentoobtainmaximum

grateareainaperiod wherelow-pitched

boilerswerethe norm andthe fireboxhad to

be setlowbetween theframes. Theengine

had aboile rthatwas much longerthan

Drummond’s standard boilers.

Anothe runusual featureofbothtypes

wasthe valvegear. Thevalvesfor theinside

cylinderswereoperatedbyStephensonvalve

gear andthe valves for theoutside cylinders

were operated by Joyvalve gear.

Therehad beenmuchearlier expe rimentation

with theconcept of asteam railcarthathad

metwithlittlesuccess ,but theideawas revived

in 1902 when Drummond builttwo K11class

railcars for an LSWRbranch linebetween

Frattonand Southsea.

Steamrailcarswereintroduced for twomain

reasons–eithertocompetewiththe new

electric tramways that were vyingfor traffic

in suburbanareas or to provideaneconomic

serviceonlightly used count ry branch lines.

Drummond’s firstunitwas lent to the

GreatWestern Railway, returningwith

favourable re ports. Butwhentheywere

introduced in thesummerof1903, theunits

struggledwithpassenger sonthe gradientson

thelineand itwasdiscoveredthatthe GWR

hadtrialledthe unit on leveltrack andwithout

passengers.The unitswererebuilt with a

bigger fireboxand boiler andtheyproved

successful,withthe GWRalso buildingits

ownunits shortlyafterwards.

Drummond’s successwithhis4-4-0

designsmeant that theLSWRwas adequat ely

equipped withexpressmotivepower.

However, trai ns were beingacceleratedand at

thesametimetheyweregetting heavier. The

4-2-2-0s were notthe answer,but Drummond

felt that a4-6-0wasneeded. He gave hisF13

4-6-0 ahugeboilertof eedfourcylinders.The

newdesignhad Stephenson valvegearfor the

inside cylindersand Walschaerts valvegear

forthe outside, crea ting aheavy andunduly

complexlocomotive.

Thefirst of five F13swas out-shopped from

NineElms in 1905,coupl ed to aDrummond

‘watercart’eight-wheeled tendertocarry

sufficient coal andwater for long journeys;the

LSWR lines neverhavingbeenprovidedwith

watertroughs.The design had been intended

to operateexpresses between Salisburyand

Exeter,but they only lastedayear, before

beingdemoted to haulingcoaltrainsbetween

Salisburyand Southampton, afar cryfrom

theirintendedrole.