Sep 23, 2019 the gresley conjugated valve gear is a valve gear for steam locomotives designed by sir nigel gresley, chief mechanical engineer of the lner, assisted by harold holcroft. I posted a video of my new bowande a4 in a couple of different places yesterday and people seemed interested in the authentic gresley conjugated valve gear on the loco. It bore many similarities to the gresley conjugated valve gear used on the original lner a1 design. Mark allatt, p2 project director and trustee, the a1 steam locomotive trust, commented, the past five years have seen dramatic progress towards our aim of completing new gresley class p2 no. Couldnt resist obtaining a model of gresley s impressive p2 locomotive. During the 1930s, sir nigel gresley rebuilt number 2364 with walshaerts valve gear on the outside cylinders and using his conjugated valve gear on the center, as well as other modifications and reclassified as b162, making the originals the b161. Its a gresley a4, like the one i posted a link to a piccie of. The gresley class p2 282 mikados were the most powerful express.
Sir herbert nigel gresley 19th june 1876 5th april 1941 was one of britains most. Thank you to charles dockstader for permission to use his windows valve gear program for the above animation. These were the largest locomotives to use this valve gear. As far as im aware only bowande have incorporated this valve gear into their gauge 1 a4s. The valve gear of a steam engine is the mechanism that operates the inlet and exhaust valves to admit steam into the cylinder and allow exhaust steam to escape, respectively, at the correct points in the cycle. The designer of our locomotive, after which it was named, patented the gresley conjugated valve gear for 3 cylinder locomotives. Copper boiler, brass boiler jacket, brass cab, brass tender, steel drivers and valve gear.
Gresleys a4 mallard holds the speed record for steam traction, traveling at 126. Aster lner a4 silver link mallard sir nigel gresley. The rebuilds were controversial and sparked much debate. In 1986 i wrote the first of the msdos versions of the software to simulate baker valve gear. Flying scotsman lner live steam 462 this model is now discontinued. Valve gear definition of valve gear by the free dictionary. A history of lentz valve gear on british steam locomotives. It is currently kept at the north yorkshire moors railway. Gresley walschaerts valve gear in motion on model lner p1 heavy freight loco. Their streamlined design gave them highspeed capability as well as making them instantly recognisable, and one of the class, 4468 mallard, holds the world record as the fastest steam locomotive.
Some of you have identified a missing handrail on the class a4. Such an engine is typically most efficient when the inlet is open for a short time, before it reaches the. The gresley conjugated valve gear was a valve gear for steam locomotives designed by sir nigel gresley, chief mechanical engineer of the lner, assisted by harold holcroft. Lner tender engine kits acr products, reigate, surrey.
Shes fully authentic she has three cylinders with fully functioning gresley conjugated valve gear for the inside cylinder which is rare for a loco of this size. Pvc pipe supplies offers the fastest turn around on all orders w the lowest prices offered online. These stylish locomotives dominated east coast services for a quarter of a century until replaced by another design that became a classic the deltic class. Gresley s conjugated valve gear was not without criticism. If you would like to make a donation towards this overhaul please click on one of the the donate buttons. Valve gear on a steam locomotive is used to control the admission of steam into the. Describes gresleys famous conjugated valve gear as used used on the middle. Gresley a4 60021 wild swan stands in grantham loco yard on the 5th april 1961. Products listed are in my stock, other uk product line is special order. The a4 class was designed by sir nigel gresley in 1935, instantly recognizable with their streamlined casing.
It enables a threecylinder locomotive to operate with only the two sets of valve gear for the outside cylinders, and derives the valve motion for the inside cylinder from them by means of levers the 2 to 1 lever and equal. Further work to the air brake pipes was done this week with a section of new pipe being fitted behind the front buffer beam to the reservoir air valve. The animations seen on this page were created with software written by. Hello, looking at your blog and relative newness to oo gauge, you might like to consider that this valve gear item is no longer being produced, as with some other hornby valve gears that i cant get, mores the pity. Enormous efforts have gone in to getting the complex shape of the streamlined casing correct and we feel that the end result is worthy of sir nigel gresley s approval. Jun, 2014 walschaerts valve gear explained duration. After being scrapped by british railways it ended up in the canadian railroad museum. This rebuild effectively made him a hybrid with stanier valve gear, running plate and cylinders, while the rest above was gresley built. Known as the a4 class, four 462 locomotives were built in 1935. Its distinctive streamlined casing has come to be a symbol of 1930s luxury and fascination with speed. Gresley conjugated valve gear was used by the american locomotive company under license for the 4122 locomotives built for the union pacific railroad between 1926 and 1930. So i have produced a short video of it in action as best i can. Gresleys conjugated valve gear on my bowande a4 the. It enables a threecylinder locomotive to operate with only the two sets of valve gear for the outside cylinders, and derives the valve motion for the inside cylinder from them by means of levers the 2 to 1 lever and equal lever.
Steam engine valve gear on the computer windows version by charles dockstader hcr 69 box 3111 california valley ca 93453 805 475 2519. Recent update on steam locomotive sir nigel gresley. The lners express pacific designs were probably the most famous of the lner locomotives. The cartazzi wedges have been skimmed by one of our volunteers to restore the correct geometry. Al l were painted silvergray and were given silver names. As they were to serve on scottish expresses, they were given famous names from scottish lore.
Sir nigel gresley is now out of traffic for overhaul. However, the suitability of this valve gear did not prevent him from trying other. New pins for the conjugated gear have been specified and drawings have gone out for quotation for their manufacture. Geared butterfly valves free savings on every order. Mar 29, 2020 a valve gear is a component that controls the intake and exhaust of steam in an engine. The main problem was that it was sensitive to good maintenance. The lner london and north eastern railway class p2 was a class of 282 steam locomotives designed by sir nigel gresley for working heavy express trains over the harsh edinburgh to aberdeen line. The remaining four locomotives were completed in 1936. Based at bridgenorth on the severn valley railway, it regularly appears on main line steam specials. The equal lever of the gresley conjugated gear has new bushes and is shown on the machine after being bored out. But, unlike thompson, peppercorn used a markedly larger grate, of 50 sq. With gresley s death the new lner cme edward thompson looked into trying to standardise the locomotive fleet and the p2 class were earmarked for rebuilding as pacifics. As far as im aware only bowande have incorporated this valve gear. Hornby a4 valve gear rubbing noise new railway modellers forums.
Steam locomotive valve gear trains magazine trains news. There can be few more iconic classes of express steam locomotive than the a4 class of pacific designed by sir nigel gresley for use on the lners east coast main line. Gresleywalschaerts valve gear in motion on model lner p1. Although initial progress on the new build progressed well the frames were made in 2014 just before those for 2007 prince of wales it has been very slow since then. This is indeed missing but unfortunately it is too late to rectify this on the production models. If you are visiting to see this object, please contact us in advance to make sure that it will be on display. It enables a threecylinder locomotive to operate with only the two sets of valve gear for the outside cylinders. Test run of my latest gauge 1 purchase gresley a4 mallard. Mar 29, 2017 hi i,,,ive recently bought two hornby a4,s,,mallard r2339 and a sir nigel gresley r2688,both supposedly new in box,never run etc,,they both look new as well,,the thing is on both of them as the wheels rotate there is a rubbing noise,just once every revolution,does anyone know how to solve it,it makes you think it is rubbing on the inside of the body but i cant see anything to. I am a member of the trust that owns and operates a4 class pacific sir nigel gresley in the uk.
It is usually possible to make very small bends in the parts concerned andor remove a little plastic inside the valance to eliminate this. Sir nigel gresley overhaul update 24 national railway. Norman mckillop, great engine driver, great trade union man and. The valve is to be returned and a new body cast and machined. His invention of a threecylinder design with only two sets of walschaerts valve gear, the gresley conjugated valve gear, produced smooth running and power at lower cost than would have been achieved with a more conventional three sets of walschaerts gear. Charlie has put this program in the public domain but is not to be sold.
Sir nigel gresley overhaul update 41 national railway. Since then i have made continuous additions and improvements to add other types of valve gear and improve functionality and ease of use. Origin of the peppercorn class a1s the a1 steam locomotive trust. The holcroft valve gear was a type of conjugated valve gear designed by harold holcroft and used on threecylinder steam locomotives of the south eastern and chatham railway secr. To realise the potential of the original gresley design. Permanent damage and solvable performance suppressions includes simulated cylinder explosion due to an excess of water in the cylinders, the virtual loss of connecting rods when wheelslip goes out of control, and the gresley conjugated valve gear breaking due to middle valve overrun when coasting at a cutoff greater than 25%. The model is spirit fired with slip eccentric valve gear, working cylinder drain cocks, sprung buffers, tender hand pump, axle pump, lubricator, pressure gauge and water gauge.
Sir nigel gresley overhaul update 38 national railway. After these initial problems were solved, gresley would use his conjugated valve gear on all of his large production locomotives, including the a4 pacific, v2 262, and d49 440 classes. The walschaerts gresley valve gear was the source of much criticism, which is partly answered in holcrofts article, where it is stated that it may be recalled that in recent times a speed of 125 m. Sir herbert nigel gresley 19th june 1876 5th april 1941 was one of britains most famous steam locomotive engineers, who rose to become chief mechanical engineer of the london and north eastern railway. Sir nigel gresley s magnificent a4 pacifics can well be regarded as the zenith of british steam locomotive development. The train department live steam locomotives and steam. And of these pacifics, the a4 is probably the most famous of all.
Eisenhower was built at the famous doncaster plant locomotive works in 1937 and was exported to the national railroad museum of the usa. Gresley class p1 delivered in 1925 100 wagon trains. Although successful enough to warrant production in quantity the distinctly syncopated beats and the tendency of the middle valve to overtravel at speed, producing an imbalance of power and. The locomotive is being built as the original was remodelled in 1938 when it was fitted with gresley motion, walschaerts valve gear and streamlined in the a4 style. However, to fit in with my modern image layout, it is about to undergo a minor transformation into new build p2 number 2007 prince of wales, currently under construction at darlington, by the p2 steam locomotive company. Other issues have been raised such as boiler seams and running issues with the valve gear. She looks absolutely stunning and has a lovely 3 cylinder exhaust beat. Shortly after our marriage in 1961 kpjs wife saw her first a4 as it. I wonder if anybody can help with a question from england. Perhaps the most celebrated example of conjugated valve gear for three cylinders is the gresley lner arrangement in which holcroft was consulted. The gresley conjugated valve gear is a valve gear for steam locomotives designed by sir nigel gresley, chief mechanical engineer of the lner, assisted by harold holcroft. Lner class a4 4498 mallard model engineering clearing house. Flying scotsman lner live steam 462 accucraft uk ltd.
The doncaster p2 locomotive trust registered charity number 1149835, plans to build a working replica of the prototype no. The mechanism is usually connected a steam engines valves, and was often used in early locomotives. Nov 24, 2012 this combination was made standard for nos. Modified valve gear to achieve full forward and reverse gear. Hornby vs bachmann a4 page 3 new railway modellers forums. The gresley conjugated valve gear is a valve gear for steam locomotives designed by sir nigel.
Darrin is the locomotive engineer for the sir nigel gresley locomotive company. The clacking is the valve gear components knocking on the valances, check whether the expansion link and the combining lever are the parts responsible. The valve gear is there to move the valve over the cylinder ports allowing steam to enter the cylinder at the correct time and then allow it to escape once its job is done. Don ashtons site devoted to steam locomotive valve gears and their design, kinematics and distribution problems, particularly for walschaerts and stephensons gears. Gresley had used conjugated valve gear, while thompson and peppercorn used three sets of walschaerts. It is hoped that the amount of alloy for the correct balance can be theoretically using solidworks software. The pair of a4 pacifics in the early morning sunshine at shildon nrm soon after their return from canadausa in late 2012. They were fitted with three cylinders and had a conjugated valve gear by which cross levers from the outside motion drove the inside piston valves. The a4 gresley 462 pacific locomotive 60008 dwight d. Steam engine valve gear on the computer downloadable freeware simulations of every kind of valve gear youve ever heard of by charles dockstader ca. It varied from the gresley method of operation by using the. Overhaul work continues across a few sites on london and north eastern railway class a4 no. Also at the front bufferbeam a new copper sealing ring was fitted to the steam heat valve. Sir nigel gresley was renowned for his pacific express locomotives, the first of which, the a1 class, entered service in 1922.
A wide variety of gear valve options are available to you, such as high pressure, low pressure. Jul 25, 2005 the valve gear was adjusted electrically, and the vaves could be set in in open posion for coasting with minimum resistance. Cock o the north rebuilt with an a4 type front end and walschaerts valve gear p2slc collection. The trailing cartazzi horn liners are worn beyond further use. Class a3 462 in o gauge from hattons page 14 hattons. The doncaster p2 locomotive trust plans to build a working replica of the prototype 2001 cock o the north as it was following the modifications made to it in 1938. The valve gear also controls the distance that the valve travels across the ports and the time that the ports open and close relative to the stroke of the piston. David percival, the railway journalist and author, celebrated his 75th birthday on the 24th september.
The order has been placed for the new motion pins for the outside valve gear and work continues on the specification for the finished sizes for the connecting rod bushes. Lner a4 pacific locomotive sir nigel gresley, british. Share your thoughts, experiences and the tales behind the art. The machining of the piston valve heads is now well underway and we expect delivery of the ones machined from blank. Nigel gresley archives the great northern railway society. The locomotives frames were cut in april 2014, at tatas steels wednesfield works. Sir nigel gresleys legendary locomotives worldwide rails. Gresley s engines were considered elegant, both aesthetically and mechanically. Instructions for download and installation the bcwrr is delighted to host charlies valve gear program on its web site.
Thirtyfive were built for passenger service on the east coast main line out of kings cross, via york. Not the simplest solution, but the gear had the distinctive feature of the drive rod having a large mass at the valve gear end, and thus a taper in the reverse direction. This locomotive was designed for the streamlined express passenger services of the lner in 1930s britain. We are holding a series of free roadshow presentations in 2019, with the seventh in. The steam locomotive lner 448960010 dominion of canada was another gresley a4 pacific built at the famous doncaster plant locomotive works in 1937 at the famous doncaster plant works.
As a result it will be built with the gresley motion, walschaerts valve gear, and a lner a4 style streamlined front. With the original hornby gordon holding his asbuilt condition shape, i figured that what he also needed was a whole new model to. Dont know for sure but it might end your frustration if others on this forum with the same x8848 problem could confirm my thoughts. Sir nigel gresley s a4, in live steam, in 2 scale to run on gauge one 45mm track. Note that the valve gear is modelled in gear with motion imparted to the valve spindle by both the crosshead.
It enables a threecylinder locomotive to operate with only the two sets of valve gear for the outside cylinders, and derives the valve motion for the inside cylinder from. The class a4 is a class of streamlined 462 steam locomotive designed by nigel gresley for the london and north eastern railway in 1935. Warranty is 1 year parts and labor of manufacturer defect al performed in house. The side valances partially covering the connecting rods and wheels were. Dec 24, 2009 the middle cylinder is inclined of 10 degrees unlike 7 which was found on the union pacific 4122 9000 series.
A4 loco showing 2 to 1 valve gear in action duration. Sir nigel gresleys a4 brunswick green middlewoodbank. Attempt to do a 3d model of a gresley valve gear youtube. All stock locomotives are inspected, lubricated and air tested by myself here. Lner class a4 4468 mallard suffered centre cylinder bigend damage indicated to the driver by. Steam engine valve gear on the computer windows version. Sources of information about sir nigel gresley and his locomotives. He was the designer of some of the most famous steam locomotives in britain, including the lner class a1 and lner class. The quality of this work is a great improvement on the original contractor installation.
He clung, for instance, to his conjugated valve gear for threecylinder engines to the point of oddity. Built at doncaster works, it was originally named gadwall, being renamed sir ralph wedgwood in march 1939 in recognition of wedgwoods sixteen years of service as chief officer of the lner between 1923 and 1939. Bottomend the jig for setting up the crank axles has been fitted to the newlyarrived return cranks. No 2002 had walschaerts valve gear and others were fitted with the same streamlined front end as the a4 pacifics.
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