AB SKF is a leading bearing and seal manufacturing company founded in Gothenburg, Sweden, in 1907. The company manufactures and supplies bearings, seals and lubrication systems, maintenance products, mechatronics products, power transmission products, condition monitoring systems and related services globally. SKF is the world's largest bearing manufacturer, employs 44,000 people in 108 manufacturing units, it has the largest industrial distributor network in the industry, with 17,000 distributor locations encompassing 130 countries. SKF is one of the largest companies among the largest public companies in the world. Sven Wingqvist, at the time a thirty-year-old plant engineer responsible for repairs and maintenance at Gamlestadens Fabriker, was dissatisfied with the performance of the ball bearings in use; these were rigid ball bearings, imported from Germany, if the long shafts on the machinery in a textile mill were the least bit misaligned, the ball bearings would become overheated and break down, bringing production to a costly halt.
In spring 1907, Wingquist presented a breakthrough – a double row self-aligning ball bearing with a spherical raceway in the outer ring, shared by both rows of balls. This allowed the inner ring to align in relation to the outer ring, with no negative impact on the function of the bearing; the new bearing solved the problem associated with misalignment of the shafts and thus did away with the frequent production stops. Self-alignment was useful in the less-than-perfect machinery of the times and in buildings with subsidence problems, the case at Gamlestadens Fabriker, since much of the land on which Gothenburg has been built is clay. On 16 February 1907, Wingqvist applied for Swedish patent No. 25406, a multi-row self-aligning radial ball bearing. The Patent was granted on 6 June in Sweden coinciding with patents in 10 other countries; the new ball bearing was successful from the outset. Three years after SKF was founded, the company had 325 employees and a subsidiary in the United Kingdom. Manufacturing operations were established in multiple countries.
By 1912, SKF was represented in 32 countries and by 1930, a staff of over 21,000 were employed in 12 manufacturing facilities worldwide with the largest in Philadelphia, United States. SKF began its operations in India in 1923 by establishing a trading outpost in Calcutta; the early operations involved importing of automotive bearings. SKF India Ltd was incorporated in 1961 following a collaboration between AB SKF, Associated Bearing Co. Ltd and Investment Corp. of India Ltd. In 1963, SKF set up its first bearing factory in Maharashtra. Assar Gabrielsson, SKF sales manager and Björn Prytz, Managing Director of SKF were the founders of Volvo AB in 1926. In the beginning, the company functioned as a subsidiary automobile company within the SKF group. SKF funded the production run of the first thousand cars, built at Hisingen in Gothenburg, beginning in 1927. SKF used one of the company's trademarked names: AB Volvo, which derives from the Latin "I roll", with its obvious connotations of bearings in motion.
The ownership of Volvo lasted until 1935. In the 1970s SKF embarked on a massive production rationalisation program in Europe. A visionary project, "Production Concept for the 80s" was launched with the aim to run the night shifts unmanned. To increase productivity and safeguard the product quality, a continuous, automatic flow of bearing rings was needed, so SKF developed the Flexlink brand. FlexLink created the multiflex plastic chain conveyor system to solve the business requirements. SKF divested FlexLink as a separate company in 1997; the SKF Group consists of 150 companies including the seal manufacturer Chicago Rawhide. Since its founding, SKF's company headquarters have been located in Gothenburg. One recent acquisition was that of Economos, part of Salzer Holding, an Austria-based seal company, Jaeger Industrial and ABBA, Taiwanese manufacturers of linear actuators; the company's clients include Rolls-Royce plc and Pratt & Whitney. It supplies bearings for Ferrari racing vehicles, used in Formula One races, is a sponsor of F1.
SKF became sponsor of Team Penske in Monster Energy NASCAR Cup Series since 2012, Then in 2017 SKF became as Brad Keselowski sponsor in #2 Ford Fusion and #22 Ford Mustang in Xfinity Series, Previously, it is Sponsor of Richard Childress Racing, Roush Fenway Racing, SKF is Sponsor of Ducati in MotoGP since 2015. Another focus area is the energy sector, including wind turbines. By 2011, SKF Industrial Market, Regional Sales and Services, made up about 40% of SKF's total sales. SKF employs 3000 people across six factories in India and has 27% market share of the industrial & automotive bearings market.2016 SKF had a total net sales of 72,787 SEKm. SKF sells products within five technology platforms: Bearings and Units Mechatronics Lubrication Systems Services Seals SKF runs its own business excellence program for continuous improvement of its business processes in all parts of the company; the program is based on previous initiatives like TQM and integrates with lean management statistical methods of Six Sigma along with related project management.
Many elements of this SKF program remind of the integrated approach of the actual EFQM model for Business Excellence. The Group ISO 50001 and OHSAS 18001 standards, its operations are certified to either ISO 9001 or applicable customer industry standards, e.g. ISO/TS 16949, AS9100 or IRIS (railwa
LMS Stanier Class 5 4-6-0
The London Midland and Scottish Railway Class 5 4-6-0 universally known as the Black Five, is a class of steam locomotive. It was introduced by William Stanier in 1934 and 842 were built between and 1951. Members of the class survived to the last day of steam on British Railways in 1968, eighteen are preserved; the Black Fives were a mixed traffic locomotive, a "do-anything go-anywhere" type, designed by Stanier, with the GWR. In his early LMS days, he designed his Stanier Mogul 2-6-0 in which he experimented with the GWR school of thought on locomotive design. A number of details in this design he would never use again realising the superiority of details not used on the GWR. Stanier realised; these were to be the LMS version of the GWR Halls but not a copy, as the Hall was too wide to run most places in Britain. They shared similar cylinder arrangement, internal boiler design and size and 6 foot driving wheel diameters. In their early days the locomotives were known as the "Black Staniers" from their black livery, in contrast to Stanier's other class of 4-6-0, the LMS Stanier Jubilee Class, which were painted crimson.
On, the nickname of the former became "Black Five", the number referring to the power classification. This was 5P5F, but from 1940 was shown on cabsides as the simple figure 5. Eight hundred and forty-two were constructed. There were a number of detail variations in the locomotives and they did not all remain in the same condition as built; some locomotives built under British Railways administration were used as test beds for various design modifications with a view to incorporating the successful modifications in the Standard Classes of locomotives built from 1951 onwards. These modifications included outside Caprotti valve gear, roller bearings on the coupled and tender axles in varying combinations, an experimental steel firebox. Other locomotives had modified draughting to "self clean" the smokebox. Numbering started from 5000, with the first twenty being ordered from Crewe Works in April 1934, a further fifty ordered from the Vulcan Foundry in 1933; the first of the Vulcan Foundry engines entered service in 1934, the entire order of 50 was delivered before the first Crewe-built engine, no.
5000, was completed in February 1935. The first 57 locomotives were built with domeless boilers with straight throatplates and a low degree of superheat, the boilers of the remaining 13 were provided with a three-row version having greater total surface area and giving less obstruction to gas flow; the original 57 boilers were converted to higher superheat and fitted with a dome. Further orders were placed with Crewe, Vulcan Foundry and Armstrong Whitworth for a total of 155 locomotives which were built with domeless boilers with straight throatplates and 21 element superheaters. All these boilers, including the early converted ones with a dome, were fitted indiscriminately to any of the first 225 engines, which could appear at various times with domed or domeless boilers. However, many of the early frames were converted to accept sloping throatplate boilers, as listed below; this modification was carried out to provide a stock of spare boilers for the early engines, which would minimise the time spent in works by engines awaiting a fresh boiler.
All locomotives from no. 5225 were fitted. All extra boilers made had the sloping throatplate arrangement, only one example of a engine having been fitted with a straight throatplate boiler is known - no. 45433. Several different patterns of boiler were used on the locomotives; the throatplate design was the most significant, but there were different numbers of superheater flues, firegrate arrangement, stay material and water feed arrangements, washout plug placement, etc. in various combinations. The following locomotives were built with straight throatplate boilers, but were fitted with a sloping throatplate boiler. Conversion was done by relocating the frame stretcher in front of the firebox; some of them reverted to straight throatplate at a date, these are shown where known. Those marked with an asterisk were fitted with a boiler which had the top feed on the front ring on the date shown. In the case of no. 45087 it had been converted. The first conversion was carried out on no. 5022, the last known was on no.
45163, preserved. 5002, 45007, 45008, 45011, 5020, 5022 reverted, 5023 reverted, 5026 reverted, 5027, 5040, 5045, 5047, 45049 reverted, 5054, 5057, 5058, 5059, 45066, 45082, 45087, 5097, 5108, 45109, 5142, 45151, 45163, 45169, 45197 + The subsequent history of 45011 is not clear. Official records have not been relocated. There is a photograph in existence dated April 1963, showing 45011 ex-works with a straight throatplate boiler and simple top feed, i.e. without the dome-like shape. NB: The official records were not always updated after around 1960/61, although some were. For example, in the case of no. 45082, it was fitted with a brand new boiler at the end of 1956, one of the last batch of four boilers that were manufactured for this class. Since it
BR Standard Class 5 73129
British Railways Standard Class 5 No. 73129 is a preserved British steam locomotive. It is the only surviving Standard Class 5 built by British Railways, fitted with Caprotti valve gear. 73129 was outshopped from Derby Works in August 1956. It was one of 30 built fitted with Caprotti valve gear. Allocated at Shrewsbury Shed, it was transferred to Patricroft Shed in 1958, it spent the rest of its working life there until it was stored at Patricroft from June to November 1967. It was withdrawn from traffic on 2 December 1967. During 73129's working life, it covered 198,359 miles - 35,814 of those in 1957. In February 1968, 73129 was sent to Woodham Brothers scrapyard in Barry, Vale of Glamorgan, South Wales. In 1972, 73129 was purchased by the Midland Railway Project Group. Preparation work for the transportation of the locomotive to Butterley was undertaken at Woodham Brothers with small working parties. In addition, many spare parts were acquired from other locomotives 73129's neighbour at Barry, 73096, now itself preserved.
Parts were taken from the only other remaining Caprotti valve geared locomotive at Woodham Brothers, 71000 "Duke of Gloucester", now preserved. Whilst stored at Woodham Brothers, the original BR1B tender was sold to a steel works for conversion into an ingot carrier. 73129 has tender number 1043. It is of the same BR1B type, but has no water pick-up apparatus, as it was from a Southern Region based engine 75079 where there was no need for the apparatus. On 6 January 1973 a convoy from Barry hauled by a British Rail Class 46 number 157 took 73129 on part of its journey to Derby Works; the convoy included 7819 "Hinton Manor", 4141 and 5164, 4930 "Hagley Hall", a Stanier 4000 gallon tender and a brake van. Assistance out of Woodham Brothers scrapyard was given by a Class 37 diesel 6978. At Kidderminster whilst dropping off the locomotives for the Severn Valley Railway the motive power was changed to a Class 25 7655. 73129 was left at Derby Works as a temporary home. By early 1975, 73129 along with Jinty 16440 had arrived at Butterley.
Restoration was started on a limited scale on 73129 shortly after the locomotive arrived at the Midland Railway Centre, now Midland Railway - Butterley, in 1975 although work began to tail off in around 1985. Another small attempt to restart the restoration was tried in 1992 although minimal work was carried out due to lack of financial and human resources. In late 1993, restoration began in earnest; this took over a decade. The first fire in 73129's firebox since 1967 was lit at 3.25 pm on 22 February 2004. Steam locomotives 92214, 80098, 47357 and Peckett 1163 "Whitehead" were all in attendance, all whistling when smoke first appeared from 73129's chimney. Midland Railway – British Railways Standard Class 5MT 4-6-0 locomotive no. 73129
A rolling-element bearing known as a rolling bearing, is a bearing which carries a load by placing rolling elements between two bearing rings called races. The relative motion of the races causes the rolling elements to roll with little rolling resistance and with little sliding. One of the earliest and best-known rolling-element bearings are sets of logs laid on the ground with a large stone block on top; as the stone is pulled, the logs roll along the ground with little sliding friction. As each log comes out the back, it is moved to the front where the block rolls on to it, it is possible to imitate such a bearing by placing several pens or pencils on a table and placing an item on top of them. See "bearings" for more on the historical development of bearings. A rolling element rotary bearing uses a shaft in a much larger hole, cylinders called "rollers" fill the space between the shaft and hole; as the shaft turns, each roller acts as the logs in the above example. However, since the bearing is round, the rollers never fall out from under the load.
Rolling-element bearings have the advantage of a good tradeoff between cost, weight, carrying capacity, accuracy, so on. Other bearing designs are better on one specific attribute, but worse in most other attributes, although fluid bearings can sometimes outperform on carrying capacity, accuracy, rotation rate and sometimes cost. Only plain bearings are used as as rolling-element bearings. There are five types of rolling elements that are used in rolling-element bearings: balls, cylindrical rollers, spherical rollers, tapered rollers, needle rollers. Most rolling-element bearings feature cages; the cages reduce friction and bind by preventing the elements from rubbing against each other. Caged roller bearings were invented by John Harrison in the mid-18th century as part of his work on chronometers. Typical rolling-element bearings range in size from 10 mm diameter to a few metres diameter, have load-carrying capacity from a few tens of grams to many thousands of tonnes. A common kind of rolling-element bearing is the ball bearing.
The bearing has outer races between which balls roll. Each race features a groove shaped so the ball fits loose. Thus, in principle, the ball contacts each race across a narrow area. However, a load on an infinitely small point would cause infinitely high contact pressure. In practice, the ball deforms where it contacts each race much as a tire flattens where it contacts the road; the race yields where each ball presses against it. Thus, the contact between ball and race has finite pressure. Note that the deformed ball and race do not roll smoothly because different parts of the ball are moving at different speeds as it rolls. Thus, there are sliding motions at each ball/race contact. Overall, these cause bearing drag. Roller bearings are the earliest known type of rolling-element-bearing, dating back to at least 40 BC. Common roller bearings use cylinders of greater length than diameter. Roller bearings have higher radial load capacity than ball bearings, but a lower capacity and higher friction under axial loads.
If the inner and outer races are misaligned, the bearing capacity drops compared to either a ball bearing or a spherical roller bearing. As in all radial bearings, the outer load is continuously re-distributed among the rollers. Only less than half of the total number of rollers carries a significant portion of the load at all time; the animation on the right shows how a static radial load is supported by the bearing rollers as the inner ring rotates. Spherical roller bearings have an outer ring with an internal spherical shape; the rollers are thinner at the ends. Spherical roller bearings can thus accommodate both dynamic misalignment. However, spherical rollers are difficult to produce and thus expensive, the bearings have higher friction than an ideal cylindrical or tapered roller bearing since there will be a certain amount of sliding between rolling elements and rings. Gear bearing is roller bearing combining to epicyclical gear; each element of it is represented by concentric alternation of rollers and gearwheels with equality of roller diameter to gearwheel pitch diameter.
The widths of conjugated rollers and gearwheels in pairs are the same. The engagement is herringbone or with the skew end; the downside to this bearing is manufacturing complexity. Gear bearings could be used, for example, as efficient rotary suspension, kinematically simplified planetary gear mechanism in measuring instruments and watches. Tapered roller bearings use conical rollers. Most roller bearings only take radial or axial loads, but tapered roller bearings support both radial and axial loads, can carry higher loads than ball bearings due to greater contact area. Tapered roller bearings are used, as the wheel bearings of most wheeled land vehicles; the downsides to this bearing is that due to manufacturing complexities, tapered roller bearings are more expensive than ball bearings. Needle roller bearings use long and thin cylinders; the ends of the rollers taper to points, these are used to keep the rollers captive, or they may be hemispherical and not captive but held
A double chimney is a form of chimney for a steam locomotive, where the conventional single opening is duplicated, together with the blastpipe beneath it. Although the internal openings form two circles, the outside appearance is as a single elongated oval; the classic exhaust design for a steam locomotive began with Hackworth's invention of the blastpipe, placed centrally within a tall chimney. Victorian developments reduced the chimney's height, such that natural draught was no longer significant; the standard design was a circular drumhead smokebox, with a single blastpipe nozzle leading into a chimney with a flared petticot pipe beneath it. From the work of theorists such as W. F. M. Goss of Purdue University, S. O. Ell of Swindon, guidelines were developed at each locomotive works, describing how these were to be proportioned, it was recognised both that a particular diameter of chimney and blastpipe would be needed for the steam-raising capacity of each boiler, that the conical taper from blastpipe to chimney could not be made too steep.
As boilers became more powerful, not only did the chimney diameter need to become greater, but the minimum height for the chimney was becoming longer – just as the increasing size of boilers restricted the clearance height available within the loading gauge. A chimney height of at least 24 inches was considered the minimum workable. By the 1930s, it was difficult to provide such a height and other solutions were sought. A solution to this limit was to adopt a double chimney; this allowed adequate cross-section area for airflow, whilst reducing the diameter of each and thus the minimum height needed for an acceptably gentle taper. A simultaneous development was the Kylchap blastpipe, combining the Kylälä spreader by Finnish engineer Kyösti Kylälä, a further flue choke tube added by the French engineer André Chapelon; this split the blastpipe area into four smaller nozzles, the vertical draught induction across three stacked venturis. Although the total blastpipe area remained constant, their perimeter, thus the area for mixing with the exhaust gases, was doubled.
The additional petticoats improved the effectiveness of the blast in inducing a draught. Although there is no reason why one approach, either the double chimney or the Kylchap blastpipe, depends on the other, interest in both was simultaneous and so both were installed together; the first 50 of the Ivatt class 4MT 2-6-0 were built with double chimneys. These performed poorly however, were noted as poor steamers. Work on the static test plant at Rugby discovered that there was both no advantage to the double chimney and that it had been poorly designed initially; when revised with a single chimney and improved gasflow in the smokebox, their steaming rate was raised from 9,000 lb/hour with a double chimney to 17,000 lb/hour with a single chimney though this was still below the theoretical limit, restricted by firegrate size, of 19,000 lb/hour. A minor disadvantage could be a'softer' exhaust blast for the purpose of lifting the external smoke clear of the driver's vision; when the LNER A3 class were fitted with double chimneys in the late 1950s, they suffered problems with smoke obscuring the view from the cab.
The solution to this was to fit small Witte-type smoke deflectors of the German pattern. Many double chimney installations, at least in the UK, were performed as experimental conversions in the 1930s, rather than as new builds. Nigel Gresley, the CME of the LNER, was a keen follower of French locomotive practice the work of André Chapelon and the Nord'Superpacifics' of Marc de Caso; when Gresley designed his P2 class as successor to his A3s, he took this French work into account and used a double chimney with Kylchap blastpipes. Two P2s were built 2001 Cock O' The North and 2002 Earl Marischal, both in 1934. Following French practice, 2001 was built with poppet valves, for comparison 2002 kept the conventional piston valves. To avoid problems with smoke obscuring the driver's vision, both were built with wedged tops to their smokebox and wing plates to the upper sides of it, as had been used for 10000. With the sharper exhaust of the poppet valve-equipped 2001, this was successful and smoke was projected upwards, clear of the cab windows.
2002 had a softer exhaust though and gave trouble, until it was rebuilt with additional smoke deflectors, spaced about 18 inches parallel to the existing wing plates. Both locomotives were considered successful, but 2002 had the edge for efficiency, put down to the smaller volumes within the valve chest; when the further members of the P2 class were built, they followed 2002 with piston valves and the extra smoke deflectors. The first of the A4 class reverted to a conventional blastpipe, they had the greatest attention paid to their gas flow both the inlet and exhaust sides. With the P2s, there had been a tendency for an excess of draught, when working hard at a long cut-off, enough to lift the fire. To avoid this, the A4s used a'jumper top' on their blastpipe, a loose ring which rose under the influence of a strong blast jet, increasing the effective nozzle diameter and so reducing the drawing effect of the blast; this device could not be applied to either a double chimney, nor to a Kylala blastpipe, but it is not clear if, the only reason for the simplified single blastpipe.4468 Mallard the 28th of the A4s was built with a double chimney and Kylchap blastpipes in 1938.
This was considered successful and so the final three of the class, built a few months were built with them. The entire class was refitted in the 1950s, together with some of the A3s. Peppercorn's A2 pacifics were built, post-war, with similar double Kylchap blastpipes. Five members of the LMS J
Horwich Works was a railway works built in 1886 by the Lancashire and Yorkshire Railway in Horwich, near Bolton, in North West England when the company moved from its original works at Miles Platting, Manchester. Horwich Works was built on 142 hectares of land bought in April 1884 for £36,000. Rivington House, the first of several workshops was 106.7 metres long by 16.8 metres wide and opened in February 1887. The long brick built workshops had full-height arched windows and were separated by tram and rail tracks. Work to construct the three bay, 463.3 metres long by 36 metres wide, erecting shop began in March 1885. Inside were 20 overhead cranes. An 18-inch gauge railway, with 7.5 miles of track was built to carry materials around the works complex, modelled on a similar system at Crewe Works. Two small 0-4-0 tank locomotives were bought from Beyer, Peacock & Company in 1887 to haul stores trains around the site, six more were acquired at intervals to 1901; the first of these was bought from Beyer Peacock.
From 1930 they were withdrawn from service, the last, was withdrawn in 1961 and is preserved at the National Railway Museum. The first locomotive built by the LYR at Horwich was a 2-4-2 tank engine designed by John Aspinall; this locomotive was L&YR 1008. By 1899 a further 677 locomotives had been built, another 220 under Henry Hoy. Between 1891 and 1900, 230 0-6-0 tender engines designed by Barton Wright were rebuilt as 0-6-0ST saddle tanks, LYR Class F16. In 1899, the Aspinall-designed'Atlantic' 4-4-2 express passenger locomotive was introduced and forty had been completed by 1902. Horwich works produced its 1,000th engine in 1907, a four-cylinder compound 0-8-0. In 1923 when the railway became part of the London and Scottish Railway, its Chief Mechanical Engineer was George Hughes. In 1926 he was responsible for the design of a 2-6-0 mixed traffic locomotive of unusual appearance, which became known as the "Horwich Crab." The class proved successful, 245 locomotives were built, 70 at Horwich, including the first 30 examples.
The "Crabs" continued in service with British Railways' London Midland and Scottish regions until the last two survivors were withdrawn in early 1967. Three of the four future Chief Mechanical Engineers of the post-grouping railways learned their craft at Horwich: Nigel Gresley, Henry Fowler and Richard Maunsell, as well as aviator Alliott Verdon-Roe who went on to found the Manchester-based Avro aeroplane company. During World War II, the works built nearly 500 Cruiser and Matilda tanks. After nationalisation in 1948, locomotive construction at Horwich continued at a high level for ten years. During 1948 twenty LMS Ivatt Class 4 tender engines were completed, twenty-seven followed in 1949, with twenty-four in 1951, followed by a single locomotive in early 1952. Between 1945 and 1950, 120 LMS Stanier Class 5 4-6-0 tender engines were built at Horwich by the LMS and British Railways; the last BR Standard design steam engine to be built was outshopped in 1957. BR continued to overhaul steam engines for several more years.
The last steam locomotive was despatched after overhaul on 4 May 1964. In October 1969 it became part of British Rail Engineering Limited. Horwich continued in use as a works for other rolling stock up until it closed in December 1983; the foundry and the spring shop continued in use after this date, although the work force was reduced from 1,400 to 300. In an effort to publicise the redevelopment of the site into small industrial units on 20 June 1985 locomotive 47491 was named Horwich Enterprise by Parliamentary Under Secretary of State for Transport David Mitchell at Horwich Works; the site was sold by BREL to the Parkfield Group in 1988 and the rail connection to the works was removed in 1989. The site is now an industrial estate, appropriately named "Horwich Loco Industrial Estate", with most of the buildings still in use. Horwich railway station in the town centre used by employees at the works, was opened in 1887, it closed in 1965 with the last passenger train departing on 27 September 1965, hauled by 2-6-4T number 42626.
The locomotive works site was designated a conservation area by Bolton Council in 2006. The site was proposed for mixed-use development in 2010 to include 15 to 20 hectares of land for employment and up to 1,600 houses within a timescale extending from 2013 to 2026; the proposal was adopted as council strategy in 2011, supplementary planning guidance was released in 2012 designating part of the site for preservation. An initial planning application was approved by Bolton Council in 2016. Work began in 2018. Horwich photos, National Railway Museum "Horwich Locomotive Works", www.warmemorials.org
Caprotti valve gear
The Caprotti valve gear is a type of steam engine valve gear invented in the early 1920s by Italian architect and engineer Arturo Caprotti. It uses poppet valves rather than the piston valves used in other valve gear. While basing his design on automotive valves, Caprotti made several significant departures from this design to adapt the valves for steam. Having agreed a joint-venture with Worcester-based engineering company Heenan & Froude from 1938, Heenan & Froude acquired Caprotti post-World War II in 1947; the Caprotti valve gear was first tested on a Ferrovie dello Stato Italiane Class 740 2-8-0 mixed-traffic locomotive in 1921. Up until the 1930s it was fitted on some 334 FS locomotives and on 77 narrow-gauge locomotives of other companies. Given their need for more complex and expensive maintenance, most of these locomotives were withdrawn from service before those with Walschaerts valve gear, in the 1960s. In August 1926, the London and Scottish Railway equipped four-cylinder 4-6-0 locomotive no. 5908 of the Claughton Class with Caprotti valve gear and poppet valves.
Following trials, nine more were rebuilt in 1928 with Caprotti valve gear, poppet valves and larger boilers, in 1928 ten others of the same class were given the larger boiler but retained the Walschaerts valve gear and piston valves with which this class was fitted, to enable comparisons to be made between the two types of valve gear. That year, no. 5908 was given a larger boiler. It was found that the Caprotti-fitted locomotives were more economical on coal and water than those with Walschaerts valve gear, but it was found that some of the losses of the Walschaerts locomotives was due to leakage of steam past the valve heads, where a single wide ring was used. New piston valves having several narrow rings were fitted to one locomotive, it was found that the Walschaerts valve gear could be just as economical as the Caprotti, but with less cost of fitment. No more Claughtons were fitted with Caprotti valve gear, the ten locomotives were withdrawn in 1935–36. On the London and North Eastern Railway, two 4-6-0 locomotives of LNER Class B3 were rebuilt with Caprotti valve gear in 1929, followed by a further two in 1938–39.
These locomotives had four cylinders, the poppet valves were mounted vertically, two at each end of each cylinder. One of the first pair of locomotives was rebuilt with Walschaerts valve gear in 1943, but the other three ran with Caprotti valve gear until withdrawal in 1946–47. In the 1950s, Caprotti valve gear was improved and this British Caprotti valve gear was fitted to the last two British Railways-built'Black Fives' 44686/7, the last 30 BR standard class 5s, numbers 73125-54, the unique BR standard class 8 71000 Duke of Gloucester. Results were mixed, with the performance of the Duke of Gloucester being disappointing; that was found to be due to errors elsewhere in the design and construction of the locomotive. Although more expensive to manufacture than its rivals, the improved Caprotti valve gear is more efficient than any other. A major improvement is that much of the mechanism is enclosed, leading to reduced wear and tear from the harsh steam locomotive environment, independent control of admission and exhaust.
The restored Duke of Gloucester, with its flaws eliminated, has proved the concept. British Caprotti Valve Gear on the Duke of Gloucester BR Standard Class 5, No 73129 with Caprotti gear, Midland Railway - Butterley