While the Fairlie locomotive has all but disappeared, the vast majority of diesel and electric locomotives in the world today follow a form not too dissimilar from Fairlies — two power trucks with all axles driven, and many also follow Fairlie's idea of being double-ended, capable of being driven equally well in both directions.
The Fairlie was invented and patented by the Scottish engineer Robert F. 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 two boilers on the locomotive, joined back-to-back at the firebox ends, with the smokeboxes at the ends of the locomotive (looking fairly conventional, until you realise the locomotive is two-faced, Janus-like). In Fairlie's original design the boilers shared a common firebox, but with separate water spaces; it was found that this did not work as well as expected, and on later locomotives the fireboxes were partitioned into two.
The locomotive driver (US: engineer) worked on one side of the locomotive, and the fireman on the other; the joined fireboxes separated them. There were, of course, controls at both ends of the central cab to allow the locomotive to be driven equally well in both directions.
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. Steam was delivered to the cylinders via flexible tubing. Couplers and buffers (where fitted) were sometimes mounted on the bogies, not on the locomotive frame, so that they swivelled with the curvature of the track.
Fuel and water were carried on the locomotive, in the form of side tanks beside each boiler for the water, and bunkers for the fuel above them.
Early Fairlie locomotives were rather unsuccessful, examples being built for the Neath and Brecon Railway and for the Queensland Railways in Australia being notably unsuccessful, in the latter case resulting in locomotives being returned to the builder.
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 , 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 Ffestiniog 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.
Locomotives were built for many British colonies, for Imperial Russia, and even one example for the United States. 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 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 an 0-4-0+0-4-0 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.
"...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 . Bocca del Montre summit in the Orizaba mountains, a distance of . 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.
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.
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 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, an 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. Two examples are preserved, one in Dresden, Germany, and one in Serbia.
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 result in the oldest of the FR Fairlies - Merddin Emrys reverting 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.