In 1900, Burma Railways received five meter-gauge Fairlie locomotives from Vulcan Foundry. They had two bogies, each consisting of three coupled axles with same-size cylinders. Their difference compared to earlier Double Fairlies was that they had two separate boilers which were not joined by a common firebox. This layout was sometimes called “modified Fairlie” in this time, but had nothing in common with the Modified Fairlies built for the South African Railways more than 20 years later.

Their fireboxes were of the Belpaire type and had Drummond cross water tubes which further increased their heating surface. Each firebox was fed by one fireman, so that three people worked in the cab. Most of the time, the locomotives took a separate water tender with them.

The first articulated locomotive ever to be operational in Africa was a six-axle Double Fairlie built by Avonside in 1875 for the CGR. This locomotive, numbered E33, was also the first locomotive in Africa with Walschaerts valve gear. It was ordered for mainlines around East London which had steep inclines.

In trials against two permanently-coupled 0-6-0T locomotives, it showed better running qualities on downhill stretches and a better fuel economy. But like all Double Fairlies, it had very limited space in the cab what made it very unpopular with crews. But in general, it was still called a successful design with some improvements to be made in the area of the joints, bogies, sandboxes and water capacity.

In 1878, a second locomotive numbered E34 was delivered that incorporated most of the suggested improvements, but without a larger water capacity. More water could be loaded into a separate tender. The biggest point of criticism was still the cramped cab, and so both locomotives were quickly removed from mainline service and used as shunters. Both were scrapped in 1903.

The Ferrocarril de Mejillones a Caracoles was a planned line that would have connected the Bolivian coast to the silver mines at Caracoles on the Altiplano, in today's Chile. Although the construction of the line only started in 1873, the first three Double Fairlies intended for that line were built in 1872 by Avonside. They had two groups of three driving axles each and carried the double works numbers 958-9, 960-1 and 962-2.

The locomotive shown in the picture was named “Escalador de Montes” or “Mountain Climber”. It is uncertain if all three actually arrived at the location of the new line. In 1877 the Bolivian government cancelled the contract since the Chilean-backed Antofagasta-Bolivia line ran in the same corridor. So ultimately, the Mejillones-Caracoles line was never opened and the fate of the locomotives is unknown.

After the “Livingston Thompson” was the last original Ffestiniog Double Fairlie to be retired due to wear and tear in 1971, consideration was given to the continued operation of the railroad with this type of locomotive. Since rebuilding the locomotive would have required too much effort, the decision was made to completely build a new locomotive. This was one of the first times in history that a heritage railway had a steam locomotive built from scratch. Today there are several examples that follow the same pattern.

Since the locomotive, christened the “Earl of Merioneth”, had to complete everyday service on the tourist line, it was built with a few differences compared to its historical predecessors. The biggest difference was the significantly larger supplies, which should allow use without many intermediate stops. Oil was used as fuel to reduce the risk of forest fires due to sparks. Despite using refurbished bogies from older locomotives, it was able to haul trains with twelve cars and 500 passengers on a gradient of 1 in 80.

After many years in service, it was converted to coal-firing to reduce costs in view of the increased oil price. The chimneys had to be fitted with spark arrestors to further reduce the risk of fire. When the boiler ticket threatened to expire in 2018, the decision to make was similar to that in the 1970s. This time, too, the decision was made to let the ticket expire and to build a new locomotive with the name “James Spooner”. Today the “Earl of Merioneth” is on display at Boston Lodge.

For freight traffic on the Reichenbach-Oberheinsdorf line, one of only two metre-gauge lines in Saxony, the Saxon State Railways got three Fairlie locomotives in 1902 which they designated I M. They had two two-axle bogies with a two-cylinder compound engine each, which were fed by two separated fireboxes in the middle of the boiler. The roof spanned the whole length of the locomotive. Since the tracks were located on the street in many places, the running gear was covered.

When taken over by the Reichsbahn in the twenties, the locomotives were numbered 99 161 to 99 163. Soon the roofs over the boiler barrel were removed. In World War II, 99 163 was shipped to Crimea, but the ship was sunken on its way. The remaining two were retired in 1963. 99 162 was preserved and on static display at Dresden between 1971 and 1974. Previously, the roof had been restored to its original form. Today it can be found at Oberheinsdorf, a former station on the line where it once operated.

Class II K consisted of two Double Fairlie locomotives built by the British firm R. & W. Hawthorn for the Saxon narrow gauge railways. Their design made them unique among the German railways, but their blatant defects prevented the procurement of more locomotives. These locomotives were ordered in search for a fitting design for lines with many curves and gradients. Double Fairlie locomotives basically consisted of two locomotives connected back to back, but had a common boiler with two fireboxes in the middle. Two two-axle bogies were mounted under the locomotives which had all axles powered.

This design was particularly suitable for the narrow curves, since the running gear was mounted on bogies and thus allowed a great deal of freedom of movement. However, their operation presented a very big challenge, at least for the second man, since he had to fire and observe both fireboxes at the same time. Added to this was the tight space in the cab, which hardly allowed freedom of movement.

Mainly for the latter reason, no further II K were ordered and instead the III K was developed. It was also stated that the weight was too high for the existing lines. Both prototypes remained in service until they were withdrawn in 1903 and 1909. Four years later, two new double locomotives were built from four I K, which were also given the designation II K. Before being named II K or K II, the locomotives were called Htn F TK, from which the characteristics of these locomotives could be derived. Htn stood for the manufacturer Hawthorn, F for Fairlie, T for tank locomotive and K finally designated all locomotives for 750 mm gauge. 

After the single 2-6-2+2-6-2 Modified Fairlie of class FC of the South African Railways, Colonel F.R. Collins specified a somewhat heavier variant that was again to be built by North British. The four locomotives were delivered in 1925 and were called class FD. They had direct competition from the class GD Garratt that had the same wheel arrangement.

In service it was found that the long rigid frame produced some problems. These included huge side overhangs when running through curves and oscillations of the water and coal tanks at speed. Also the pivot bearings had to support considerably higher weights due to the supplies being on the main frame. So ultimately the GD Garratts were more successful with 14 built. All FD locomotives were scrapped in 1949.

The class HF was a 2-8-2+2-8-2 Modified Fairlie that did not only have two driving axles more than the preceding classes FC and FD, but also a higher axle loading. The class designation should have been “FE”, but obviously “HF” was chosen to denote it as a “Henschel Fairlie” in contrast to the other Fairlies built by North British. It had a direct competitor in the class GE Garratt with the same wheel arrangement that was introduced two years earlier.

When put into service, they had some problems with steam production which had to be addressed in the Durban Workshops. A general problem of Modified Fairlies were the overly long frames which did not only have to carry the boiler, but also the supplies. So there were often cracks in the frames and also the pivot bearings were subject to a huge amount of wear and tear. So all in all, they were not as successful as the Garratts and no further Modified Fairlies were ordered by the SAR. The eleven class HF locomotives were withdrawn by 1951.

The “Seraing” was one of the four locomotives that took part in the Semmering competition. Its name came from the Belgian city where its manufacturer was based. It had two complete boilers which met in the middle at the firebox. Two power plants were each in a bogie. The locomotive thus anticipated the design of the Double Fairlie and is said to have basically met the requirements.

The biggest problem, however, was that the manufacturing methods for the flexible steam pipes at that time were not yet mature enough to remain permanently leak-proof. The amount of dry steam that could be extracted from the boiler was also said not to have been sufficient. It eventually finished third in the competition and was not used for long.

For the mining of lead in the west of Western Australia, the Avonside Engine Company built two Double Fairlies for the WAGR in 1879. Each half had two driving axles and one leading axle. Unfortunately, the price of lead was falling in these times and so both were stored at first after delivery. Finally, they were placed into service in 1881 and 1885, respectively. Designated class E, they received the numbers E20 and E7. In 1888, they came to Fremantle. Only three years later, one half of E20 was rebuilt into the conventional 2-4-2T locomotive numbered F20, while the other half was scrapped. E7 was scrapped in 1897, but F20 was used until 1905.