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A Fairlie is a type of articulated steam locomotive that has the driving wheels on bogies. The locomotive may be double-ended (a double Fairlie) or single ended (a single Fairlie). Fairlies are most associated with the Ffestiniog Railway in Wales.
While the Fairlie locomotive has all but disappeared, the vast majority of diesel and electric locomotives in the world today follow a form not very different from the Fairlie — two power trucks with all axles driven, and many also follow the Fairlie's double-ended concept, being capable of driving equally well in both directions.
The Fairlie was invented and patented by the Scottish engineer Robert Francis Fairlie in 1864. He had become convinced that the conventional pattern of locomotive was seriously deficient; they wasted weight on unpowered wheels (the maximum tractive effort a locomotive can exert is a function of the weight on its driving wheels) and on a tender that did nothing but carry fuel and water without contributing to the locomotive's adhesive weight. Furthermore, the standard locomotive had a front and back, and was not intended for prolonged driving in reverse, thus requiring a turntable or wye at every terminus.
Fairlie's answer was a double-ended steam locomotive, carrying all its fuel and water aboard the locomotive and with every axle driven. The double-ended part was accomplished by having one double-ended boiler on the locomotive, with one firebox in the centre and a smokebox at each end. The locomotive looked fairly conventional until the observer realised that the locomotive was two-faced, Janus-like.
The first loco was The Progress built for the Neath and Brecon Railway. However, having the draught from both halves of the boiler through one firebox was unsuccessful. There was a tendency for most of the hot gases from the fire to go through one half of the boiler, so the other half made little contribution to steam-raising and was inefficient. The first Ffestiniog Railway Fairlie - Little Wonder - had separate fireboxes and proved far more successful.
The locomotive driver (US: engineer) worked on one side of the locomotive, and the fireman on the other; the fireboxes separated them. The regulators for both power bogies were located above the centre of the fireboxes, with the steam brake valve at one end.
Underneath, the locomotive was supported on two swivelling powered bogies (US: trucks), with all wheels driven; smaller locomotives had four-wheel bogies, while larger had six-wheel. The cylinders on each power bogie pointed outward, towards the locomotive ends. Couplers and buffers (where fitted) were mounted on the bogies, not on the locomotive frame, so that they swivelled with the curvature of the track.
Steam was delivered to the cylinders via flexible tubing. Initially, this was a coiled copper tube but this would fracture after a period of use. Later locomotives had rigid connecting tubes with the necessary flexibility provided by metal ball-and-socket joints similar to those used in laboratory glassware.
Fuel and water were carried on the locomotive, in side tanks beside each boiler for the water, and bunkers for the fuel above them.
In 1869 Fairlie's company built a locomotive, named Little Wonder (Fairlie was not an individual given to modesty) for the Ffestiniog Railway, a slate hauler in north Wales, and this one proved to be an outstanding success. Particularly important for a narrow gauge line as small as the Ffestiniog, with a gauge of 1 ft 11.5 in (597 mm), was the fact that the Fairlie design meant that the fireboxes and ashpans were not restricted by frame or track width, but only by the overall loading gauge. Little Wonder was such a success that Fairlie gave the Festiniog Railway Company a perpetual license to use the Fairlie patent without restriction in return for using the line and the success of its Fairlie locomotives in his publicity. The Ffestiniog went on to own a total of six Fairlie locomotives, with three in service in 2011, and one on display at the National Railway Museum.
Armed with the success of Little Wonder on the Ffestiniog, Fairlie staged a series of very successful demonstrations on the Ffestiniog line in February 1870 to high-powered delegations from the many parts of the world. This sold his invention (and the concept of the narrow gauge railway on which it was based) around the world.
In 1879 the first government railway line in Western Australia from Geraldton to Northampton utilised a Fairlie for one of its first items of rolling stock. The only really successful uses of the Fairlie locomotive, other than on the Ffestiniog Railway, were in Mexico, New Zealand and Russia on Transcaucasian Railway.
The locomotive sold in the US was ordered for the newly built Denver and Rio Grande Railroad in 1872, and was a smaller locomotive with four-wheel bogies, giving it a 0-4-4-0 configuration. The railroad's experience with the locomotive was typical, and an indication of the fact that, though Fairlie had eliminated several problems of the conventional locomotive, he had introduced new ones of his own. At least one double Fairlie 0-6-6-0 (pictured above) was built by the Mason Machine Works in Taunton, Massachusetts.
The Toronto and Nipissing Railway used a single 1,067 mm (3 ft 6 in) gauge Fairlie from 1871 until the line was converted to standard gauge in 1883.
In Mexico the Ferrocarril Mexicano (FCM) used Fairlies on a mountainous stretch of line between Mexico City and Veracruz, where 49 enormous 0-6-6-0 Fairlies weighing about 125 tons apiece were imported from England. The largest and most powerful locomotives built there up to then, they were used until the line was electrified in the 1920s. The tractive effort figures (see table below) are impressive compared to a relatively modern locomotive, e.g. the BR Standard Class 9F.
"...it was the Mexican Railway that became Fairlie's most devoted adherent. Three twelve-wheeled Avonside Fairlies were built for this Company in 1871 to work traffic on the steeply graded section of the main line between Cordoba and the 7,923 ft (2,415 m). Bocca del Montre summit in the Orizaba mountains, a distance of 108 miles (174 km). So successful were they that they were the forerunners of no less than fifty Fairlies supplied to Mexico by Avonside and other British builders over a period of forty years."
Durrant took a more sceptical view:
"The largest Fairlies built were...102 ton examples for the Mexicano Railway...Despite their impressive proportions, these engines were devoid of superheaters or modern valve arrangements and were soon replaced by electrification."
This table shows brief details of the locomotives. Detailed specifications can be found at steamlocomotive.com 
|Class||Road numbers||Date||Builder||T.E. (lb.)||Weight (lb.)||Notes|
Durrant shows a photograph (credited to English Electric) of FCM number 184, built by Vulcan Foundry (VF) in 1911. This is of typically British appearance apart from the sanding dome which, curiously, is provided at one end only. This photograph of FCM number 183  shows a locomotive of distinctly American appearance. If it is one of the VF engines, it has certainly been heavily re-built.
The VF engines were almost certainly built as oil-fired. The photograph in Durrant's book looks like a works photograph showing the engine in new condition and there are rectangular tanks on top of the boilers, which was the usual arrangement on oil-fired Fairlies. Heat from the boilers kept the oil warm and prevented it from becoming too viscous in cold weather.
In New Zealand the R class and S class single Fairlies and the B class and E class double Fairlies were ordered in the 1870s for use on the narrow gauge (3' 6") system built under Julius Vogel's 1870 "Great Public Works" programme to open up the country. Three of the S class Fairlies were sold to Western Australia Railways in 1891.
In Russia, Fairlies were used on a line between Tambov and Saratov (1871–1887) and on Surami Pass of the Transcaucasian Railway (since 1872). These locomotives, like the ones used in Mexico were an 0-6-6-0 configuration. The first of them were built in England (Avonside Engine Company, Yorkshire Engine Company and Sharp Stewart and Company), the second tranche were made by German factories (1879), the last – by Kolomna factory (1884) under licence. The largest locomotives weighed 90 tons and were oil-fired. In 1912 all Fairlies in Russia were included in series F and used until 1934, when the line through Surami pass was electrified.
Most critical was the absence of a tender, meaning that the capacity for fuel and water was very small. A locomotive is already a crowded place, and Fairlie's design gave even less room to place its supplies than a normal tank locomotive, which at least has a space behind the driver's cab to fill. Moreover, the central position of the cab meant that it was hard to add a tender later. As was later the case with Bulleid's Leader class locomotives, limited fuel supplies would not have been a problem if fuel oil had been used instead of coal. Some of the large Fairlies for Mexico (see above) were oil-fired and oil-firing has, in recent times, been used on the Ffestiniog Railway (see below).
Also problematic were the flexible steam pipes to and from the cylinders of each swivelling engine; they were prone to leakage and wasting of power. These problems were partially solved. It is recorded by Rolt that difficulties encountered in 1909 with the design and construction of steam-tight flexible steam connections for the Garratt locomotive were solved by Beyer-Peacock's designers after studying a description of the spherical steam joints used on a Fairlie locomotive built for the Ffestiniog Railway followed by a visit to the FR to observe these locomotives at work.
A further problem lay in the power bogies; there was a good reason for unpowered wheels on a steam locomotive, in that they served a function of stabilising the locomotive, reducing its tendency to wander or 'hunt' when rolling on straight track, and leading the locomotive into curves and thereby reducing derailments. Early Fairlies had a tendency to be rough-riding, rough on the track they rode, and more prone to derailment than they should have been. This was certainly in part true of Little Wonder, which was worn out and replaced by the FR after less than twenty years intensive use. It has been said[by whom?] that it[clarification needed] literally shook itself to pieces on the rough track. To a large extent the problem was not the use of power bogies but faults in their design and especially the absence of weights on the trailing ends of the bogies to counterbalance the cylinders. Subsequent FR engines were much easier on the track. All FR Fairlies have had a reputation for a smooth footplate ride when compared with the original George England built 0-4-0 engines.
The driver is on one side of the firebox and the fireman on the other. As a result, the locomotive is left-hand drive going in one direction and right-hand drive in the other. This would not help with visibility of signals.
Fairlie's vision was limited by the limitations of the steam locomotive — its thirst for water and the unbalancing forces of its directly driving pistons.
A variation of the Fairlie that enjoyed some popularity, especially in the United States, was the single Fairlie, essentially half a double Fairlie, with one boiler, a cab at one end, and a single articulated power bogie combined with an unpowered bogie under the cab, maintaining the ability to negotiate sharp turns. This design abandoned the bidirectional nature of the double Fairlie but gained back the ability to have a large bunker and water tank behind the cab, and the possibility of using a trailing tender if necessary. The single conventional boiler made maintenance cheaper and did away with the crew's separation. A fair number were built, especially by Fairlie's licensee in the United States, William Mason, who built 146 or so Mason Bogies. In the UK, a single Fairlie 0-4-4T was used by the Swindon, Marlborough and Andover Railway and three 0-6-4T by the North Wales Narrow Gauge Railways.
Interestingly, in both the UK and the USA, these single Fairlies were the first locomotives in each country to use the European Walschaerts valve gear. The Stephenson link gear, which was usual at the time, used multiple eccentrics between the frames but the Walschaerts gear was mounted outboard of the frames and connecting rods. This was advantageous because the Fairlie system required this space between the frames for the bogie pivot.
The Péchot-Bourdon locomotive was the final development of the Fairlie type. The Péchot-Bourdon was developed by Captain Péchot of the French artillery to operate on 600 mm (1 ft 11 5⁄8 in) gauge railways associated with field artillery and fortresses. The design was chosen with the belief that if one boiler or set of valve gear was damaged by enemy fire, the loco could continue to operate. The primary difference between a Fairlie and the Péchot-Bourdon is that the latter only had one steam dome. Only one design was constructed, a 0-4-4-0. About fifty examples were constructed in 1906, and a further 280 were constructed during World War I, some by the American Baldwin Locomotive Works.
A 1:32 scale model of the Péchot-Bourdon locomotive is produced by Scalelink.
The Modified Fairlie was introduced by the North British Locomotive Company to South African Railways in 1924. It was similar in appearance to a Garratt but the boiler, fuel and water tanks were all mounted on a single frame which was pivoted on the power bogies. This arrangement differs from the Garratt in which the fuel and water tanks are mounted directly on the power bogies.
The Ffestiniog Railway in Wales still uses Fairlie patent locomotives to this day; it has three double Fairlies and one single Fairlie in running condition. The most recent double Fairlie locomotives, Earl of Meirioneth and David Lloyd George, were built in 1979 and 1992 respectively in the Ffestiniog's own Boston Lodge works. The veteran Merddin Emrys of 1879 was the first engine to be built at Boston Lodge. The Ffestiniog also owned and operated Taliesin, a single Fairlie, from 1876 to 1927. It was scrapped in 1935 but a replica was built at Boston Lodge in 1999.
The Fairlies on the Ffestiniog Railway were designed to burn coal. Following trials in 1971, in common with most other Ffestiniog engines, they were modified to burn oil. In 2005, Earl of Merioneth was converted to coal having been built as an oil burner. The success of this conversion resulted in Merddin Emrys, the oldest of the FR Fairlies, being converted back to coal burning in 2007.
The oldest Fairlie still in operation is a Mason Bogie preserved at the Henry Ford Museum in Dearborn, Michigan. The 0-6-4 locomotive was built in 1873 and still hauls passengers on a tourist train during the summer season.
No other Fairlies operate today, though two are preserved in New Zealand's South Island: Josephine (Dunedin & Port Chalmers Railway #2, NZR E 175, PWD #504), a double Fairlie, at Dunedin's Otago Settlers' Museum, and R 28, a single Fairlie, at Reefton. R 28 is considered by some enthusiasts to be the only extant original British Single Fairlie, the Ffestinog's Taliesin being a replica from 1999. The remains of another, R 271, were dumped at Oamaru to protect the railway yards against coastal erosion in 1930, and have since passed into the ownership of the Oamaru Steam & Rail Society. Two more R class boilers, and two power bogies from one each B and E class Double Fairlies are held by the Canterbury Railway Society at their Ferrymead Railway in Christchurch. A double Fairlie tramway type engine is also preserved in Eastern Germany, and one of the original Ffestiniog locomotives, Livingston Thompson of 1885, is in the National Railway Museum in York.
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