classes london classes locomotives represented distinct stages history british pacific steam locomotives designed designed main line passenger services initially great northern railway constituent company london amalgamation standard design change class designation reflected fitting chassis higher pressure boiler greater surface small reduction cylinder diameter leading increase locomotive weight eventually locomotives rebuilt specifications completely rebuilt class names locomotives came variety sources named parent company given names high ranking railway officials given names famous named company famous long distance passenger train sole survivor class preserved class great northern genesis new pacific locomotives built plant design chief mechanical engineer intention produce engine able handle assistance mainline express services reaching limits capacity large initial pacific project elongated version design cylinders finally realising design took model new american pennsylvania railroad class turn updated series prototypes scientifically developed chief consulting engineer pennsylvania prototype designed cole descriptions locomotives appeared british technical press time gave elements necessary design thoroughly date locomotive design features construction history great northern sir introduced board ordered class locomotives construction time formation line philosophy cole prototypes built maximum limits loading gauge large boiler wide giving large area set low rested trailing carrying axle unlike flat topped variety round topped line tradition features common american types downward profile boiler tapering heat transfer flow gases helped use chamber extending forward space boiler barrel boiler tube length limited feet features inherited type present earlier cole prototypes boiler pressure rated pounds square inch class pacific locomotive type incorporate universal cylinder layout cylinders drove middle coupled axle outside set inside displaced degrees allow inside cylinder valve gear derived motion inside valve outside valve eliminated inaccessible middle set valve gear frames feature soon abandoned unusual bar version slide bar adopted type slide bar locomotives later taken british railways standard designs period great northern railway incorporated newly formed result grouping appointed chief mechanical engineer new company second largest big railway companies britain realising need adopted design standard express passenger locomotive main line designating locomotive classification system choice comparative trials equivalent classified locomotives built remainder designed work bounds great northern railway meaning maximum distances miles grouping locomotives required far greater operating range early improvements number renumbered named occasion displayed member great western railway castle class number weighed long tons short tons pacific claimed powerful locomotive britain effort rated lbf following months railway companies ran comparative exchange trials types emerged triumphant castle learned valuable lessons trials resulted series modifications carried number changes valve gear included increased lap longer travel accordance practice allowed fuller exploitation expansive properties steam reduced pressure exhaust transforming performance economy economies coal water consumption achieved psi undertake long distance non stop runs previously impossible followed complete redesign valve gear applied centenary rest class modified course locomotives modified valve gear slightly raised running plate cylinders order room longer combination necessary longer valve travel modification number enterprise fitted psi boiler closely followed locomotives incorporated variations cylinder diameter size comparative purposes led radical departure practice increasing number large tubes containing elements increasing surface area contact hot gases raising steam temperature presence larger recognised square covers feature locomotives retained rest existence flying exhibited time sent class outcome experiments modifications late 1920s new class super pacific example number locomotive appeared august psi boiler inch cylinders increased long travel improved modified weight distribution new development left hand drive convenient right handed sighting signals resulting modification earlier locomotives seven built new little variation new type boiler dome oval steam collector placed rear boiler ring dome hidden beneath north subsequently constructed device standard fitting large wide boilers applied new locomotives applied replacement boilers original class locomotives eventually rebuilt class specifications drawn process lasted sir locomotive converted left hand drive took longer continued fifties experiments despite having settled new standard type continued experiment individual locomotives experiments installed increase efficiency deemed insufficient apparatus eventually removed number received ingenious design automatically varying steam passages subjected smoke trials following accident london midland scottish railway poor visibility included modification upper area surrounding chimney originally retained order form air exit chimney found ineffective stage cut retaining sloping plate directed air flow upwards lifting smoke locomotive original chimney replaced double pipe variety miniature plates added angled concentrate air flow locomotive smoke lifting devices priority normal single chimney double chimney subsequent fitting double exhaust continued pose problem regard small wings chimney finally 1950s acquired type plates original coupled traditional type tender coal rails design traced days variant enlarged wheel version carrying long tons short tons coal imperial gallons gal water new special type tender body built new non stop train tender corridor connection access tunnel water tank modern design high sheets curved coal capacity long tons short tons order able pack extra ton coal single coal rail provided particular series later deemed unnecessary corridor built non corridor version similar design followed ton coal capacity coal rail series types disc wheels instead previous variety operational details pre war performance early match performances demanded early 1920s certainly able loads single handed capacity atlantic predecessors shown test run took coach train weighing long tons short tons miles london average speed miles hour cost heavy coal consumption general performance ultimate potential design largely earlier cylinder design standard motion combined long valve travel practical problems experienced components quickly suffering premature wear especially main bearing large fitted necessary ball race excessive play led travel middle valve began hit end covers order prevent applying gear fell shortening valve travel exhaust speed responsible heavy coal consumption advantages gained locomotive revolutionary design incorporating great western inspired valve modifications economies coal water consumption achieved psi undertake long distance non stop runs previously impossible spectacular outcome occurred called daily work train non stop miles london edinburgh initially took turns service modifications gave locomotives greater speed potential proof came high speed car diesel service provided limited accommodation passengers proposed use steam traction similar service speeds carriages trial return run london leeds modified locomotive number return trip coaches weighing long tons short tons attained mph outside little lincolnshire yards earlier claims speed notably locomotive run generally considered reliably recorded instance later trial run newcastle number reached miles hour hauling long tons short tons spot maintaining speed mph consecutive miles world record non streamlined locomotive shared wartime service cylinder types suffered low wartime maintenance standards conditions designed sudden death successor help matters respect thompson took opportunity rebuild class specification divided drive separate valve gear inside cylinder thompson intended rebuild configuration converted standard meantime remaining reclassified rebuilding locomotives happened instead conversion standard continued classified reclassified designed constructed class post war recovery cylinder drive arrangement continued bring number practical problems root probably need inside cylinder inclined order space inside connecting rod clear leading coupled axle time inside valve parallel outside ones derived motion problem overcome called twist ports passages carried steam cylinders consequence length passages greater generally recommended increasing dead space combined shorter exhaust passage net result different working conditions middle cylinder outside contributing problem outside valve multiplied valve gear anticipated design stage overall consequence inside cylinder tendency power speed increased leading inside connecting rod especially big end liable fail experiments tried years cure chronic end steam era real solution found methods manufacture big end bearing problems persisted stiff overall design flaws hampered maintenance spite introduction recent middle 1950s types continued quasi monopoly express passenger services approached went series improvements comparable 1920s significant fitting french double exhaust system entirely persistence assistant locomotive shed modifications greatly reduced exhaust pressure making locomotives economical free running kept clean reducing turn time able fit intensive diesel locomotive workings arrangement universally applied streamlined non streamlined locomotives soft exhaust gave rise smoke drift driver forward vision solution came form narrow german style smoke somewhat changed appearance locomotives days prototype locomotive number rebuilt virtually new design withdrawn followed class remained intact operating express passenger work class member withdrawn british railways number prince january accidents incidents general strike locomotive hauling express passenger train deliberately south northumberland december grand parade destroyed rail accident ran rear standing train snowy conditions driver survived minor injuries locomotive tender buried following coaches passengers railway crew killed accident class locomotives production time replacement built number august locomotive hauling passenger train run error people killed injured october locomotive hauling express passenger train northumberland excessive speed crossover people killed injured february freight train divided london rear portion able run cross slow line fast line error locomotive hauling parcels passenger train collided wagons august locomotive hauling passenger train crashed york station december coaching stock train rear end collision freight train locomotive night hawk hauling freight train ran wreckage freight train ran wreckage preservation sole surviving member flying locomotive withdrawn service british railways sold preservation overhaul worked number including non stop london edinburgh run final year steam traction british railways publicised appeal purchased york fiction railway series children books character loosely based according people history railways gordon experimental prototype locomotives called built gordon sold fat controller testing complete following problems valve gear gordon substantially rebuilt cylinder chassis designed fat controller explains gordon look exactly like books models tri later produced models continuously 1960s 2000s produced live steam examples chassis initial class models manufacturers produced models scales gauge gauge
LNER Gresley Classes A1 and A3