For the 1886 World's Fair in Edinburgh, the Caledonian Railway had a single locomotive built with seven-foot wheels that would be able to travel at a very high average speed. The 4-4-0 of the class 66 by Dugald Drummond was used as the basis, in which the rear coupled axle was replaced by a trailing axle and the remaining driving axle was equipped with larger wheels. In order to be able to compensate for the low adhesion mass, a modern sanding system was used. Although a steam-powered system was just being introduced at the time, a different approach was being pursued here. Because Caledonian used Westinghouse air brakes instead of the vacuum brakes common in Britain, the compressed air was used to power the sand.

No. 123 in the Glasgow Transportation Museum

Hugh Llewelyn

After the World's Fair, locomotive number 123 was used in express service on the West Coast Main Line in Scotland. In the years 1888 and 1889 it got caught in the middle of the “Race to the North”, in which various railway companies on the east and west coasts unofficially tried to find the fastest journey time from London to Edinburgh. With often only two or three passenger cars, the locomotive did very well despite the inclines. On the 100 miles long section from Carlisle, average speeds of over 50 mph were regularly reached, on one occasion even 59. In addition to being used in front of heavier trains in combination with another locomotive, it was also used for special tasks. These included passenger trains for the Caledonian's inspectors and directors, and also repeatedly used as the lead locomotive for the royal family's train when they were en route to Balmoral Castle. The locomotive was taken over by the LMS in 1923 and was not withdrawn until 1935, making it the last British express locomotive with only one driving axle. From 1958 it ran again in front of special trains and is now in the Transport Museum in Glasgow.

After the Class C with a 4-4-0 wheel arrangement and 6 ft 7 in wheels, the Shanghai-Nanjing Railway ordered four more locomotives that were to have even larger wheels. Using a boiler that was largely the same as that of existing classes of the company, one driving axle now had to be sufficient. Despite this, the boiler was the largest ever to be found on a British-made single-driver locomotive.

The engines were intended for express traffic as part of a large trade fair in Nanjing and should be up and running within 45 days of receipt of the order. Despite the national mourning for the death of King Edward and the Pentecost holidays, the time had come after 47 days. Their special position was underlined by the fact that they were painted in a bright yellow instead of the usual green.

The Great Central Railway Class 13 was the last single-driver express locomotive to be built in Britain and one of the last to see regular service. It was developed by Harry Pollitt, who called it Type X4. It had 7 feet 9 inches diameter wheels and had a boiler pressure of 200psi from the factory. Since, despite the sophisticated sanding system that was obligatory on the last singles, there was more power than could be converted into traction, the boiler pressure was soon reduced to 160 psi. 

When Pollitt retired in 1900 and John G. Robinson took over as chief engineer at GCR, the class 13 was just being produced. Anticipating the imminent end of the singles, Robinson reduced the order from ten to six. These locomotives initially ran the important route from Sheffield to London, but were moved to Cheshire in 1903 and replaced by the 4-4-0 Robinson class D4 locomotives. Four examples were fitted with a superheater between 1915 and 1919, but they were all retired between 1923 and 1927.

The Great Eastern Railway's P43 class was the penultimate single-driver express locomotive built in Britain, before the GCR Class 13. Although the GER was already using four-coupled passenger locomotives, its seven-foot wheels were used to pull light express trains. The usual area of application included the fastest possible transport of wealthy customers from the City of London to the North Sea coast in Norfolk.

Its developer James Holden is considered one of the pioneers of oil firing, and so the P43 also had oil firing. This could be seen in the different shape of the tender, which was also prepared for conversion to coal. As an oil tender, it held 715 gallons of oil and 2,790 gallons of water. The necessary pre-heating of the oil was accomplished by feeding the oil in the tender through a tube through which the exhaust steam from the brake system ejector was also fed.

Schematic drawing

Locomotive Magazine, June 1912

Even if they had slightly smaller driving wheels compared to other British singles and the adhesive weight was low for the time around the turn of the century, they were initially able to hold their own with their light trains on the relatively flat route. Nevertheless, the first two of the ten locomotives were retired in 1907, followed by five in 1908, one in 1909 and the last two in 1910. They were replaced by the 4-4-0 locomotives of classes S45, D56 and H88, also developed by Holden, which were called “Claud Hamilton”.

Patrick Stirling believed that locomotives with large wheels would not only be suitable for higher speeds, but would also achieve better traction. So he borrowed a 2-2-2 locomotive from the Great Eastern and used it to develop a significantly larger locomotive. By adding a two-axle leading bogie, guidance at higher speeds was improved and the increased weight was better distributed.

The no longer operational No. 1 in July 2003 in Doncaster

Our Phellap

The driving wheels were eight feet and one inch in diameter, equivalent to 2,464 mm. The cylinders were very large at 18 by 28 inches in order to still be able to convert enough steam at the lower rotational speeds of the large wheels. In order to be able to position the boiler low despite the large cylinders and also to avoid the problems with cranked axles and high forces, the cylinders were arranged on the outside. Between 1870 and 1895 a total of 53 were manufactured, which became increasingly heavier and had a higher boiler pressure.

sectional drawing

Locomotive Magazine, February 1902

The Singles were also used on heavier trains on the flat line between London and York with an average speed of around 50 mph or 80 km/h. Trains with ten to 16 three-axle coaches that weighed between 150 and 240 tons in total were common on lines that rarely had a gradient of more than 1 in 200 and a maximum of 1 in 95. With lighter trains, they could reach speeds of up to 85 mph or 137 km/h.

In the “Race to the North” they ran lighter trains at average speeds of more than 60 mph or 97 km/h. Even with heavier trains, there were strict instructions not to use pilot locomotives in order to showcase the performance of the Singles. After there were two derailments in 1895 and 1896 due to the high axle load on the driving axle, the weight was reduced.

At the turn of the century, the trains became too heavy for the Singles, so pilot locomotives were now used. With the introduction of Ivatt's Atlantics in 1898, the area of operation also shifted to less important trains. Nevertheless, some received a larger domed boiler by Ivatt. After the last ones were retired by 1916, only number 1 remained as the oldest Single from 1870. It ran for the last time in 1985 and is now in the National Railway Museum in York.

Based on the success of the Firefly class, Daniel Gooch wanted to build an even more powerful and faster express locomotive. The driving wheels were increased from seven to eight feet and the largest possible boiler was installed in order to be able to take full advantage of the broad gauge. The wheel arrangement was still 2-2-2 and all wheels were mounted between the inner and outer frames. The cylinders were mounted between the inner frames.

“Great Western” in its original condition

Die Lokomotive, September 1937

The “Great Western” was completed in 1846 as the forerunner of the series. After just a short trial, the leading axle broke, which was attributed to the fact that the locomotive was too heavy to distribute the load over just three axles. The solution was to replace the leading axle with two axles that were also mounted in the frame. Although this made the locomotive heavier overall, the load on the driving axle fell. A further 29 series pieces were built in this form. The class was named “Iron Duke” after the first newly built machine and is said to have reached a top speed of 78 mph. The five-car express between London and Bristol is said to have averaged 68 mph on the 53 miles long section to Didcot.

“Great Western” with fixed leading axles

Die Lokomotive, September 1937

In 1871 the “Great Britain”, “Prometheus” and “Estaffete” locomotives were converted to the Rover class. They received a larger boiler with higher pressure and a flat, elevated firebox instead of the previous haystack-shaped firebox. While the Iron Duke class locomotives were gradually phased out, their names were reused for 19 newly built Rover class examples, produced up to 1888.

The last engines of the Rover class did not have long lives, as broad gauge operations ceased in 1892. All pieces were then scrapped. It was not until 1985 that a working replica of the Iron Duke was built using parts from two Hunslet Austerity tank locos. It was not restored to service after her boiler life expired and now stands at the Didcot Railway Centre.

The Class 3031 of the Great Western Railway, also known as the “Dean Single”, was created from the conversion of 30 examples of the Class 3001, which had been built by William Dean in the 7 feet 1/4 inch broad gauge and were converted to standard gauge a short time later. Since an increase in power through a wider boiler was impossible with the standard gauge due to the limited space between the large wheels, the boiler was extended to the front. After the leading axle derailed in the middle of the box tunnel due to the increased weight, it was replaced with a bogie, resulting in the class 3031. Since the cylinders were located below the smoke box in class 3001, a special bogie had to be constructed. This could be pulled out after loosening four screws and slightly lifting the front part of the locomotive to ensure uncomplicated maintenance of the smoke box and cylinders.

No. 3050 “Royal Sovereign”

J.R. Howden, The Boys' Book of Locomotives

First, two class 3001 locomotives were converted in March 1894, the remaining 28 were converted between June and December of the same year. A total of 50 more were factory built between 1894 and 1899. In use, the class 3031, like other locomotives with a 4-2-2 wheel arrangement, excelled with high sustained speeds. On May 9, 1904, a mail train was able to travel the 117 miles from Bristol to London-Paddington in just under 100 minutes for the first time, which corresponds to an average speed of around 70 mph. However, since one driven axle was soon no longer sufficient, they were decommissioned between 1908 and 1915. Today there is a replica of No. 3041 “The Queen”, which was completed in 1982.

After the Midland Railway had already procured 70 examples of express locomotives in the 4-2-2 wheel arrangement in the late 1880s, the era of express locomotives without a second coupled axle was already considered over. However, the Midland followed the strategy of using smaller locomotives, which were then supported by a second locomotive when required. Then, when steam-powered sanders were introduced, Samuel Waite Johnson developed another single express locomotive.

Inner and outer frames were used to safely transmit the forces of a powerful express locomotive to just one axle. Thus, the driven axle had four bearings and could easily withstand the forces of the internal cylinders. After five examples of the class 115 built in 1896 and 1897, another ten units were built in 1899.

Also in 1899, the class 2601 was presented, of which ten examples were built. The driving wheels were half an inch larger, the boiler pressure was increased from 170 to 180 psi, and the firebox was larger. In addition, the slide valves were replaced with piston valves. Instead of the previous three-axle tender, now a four-axle one was used.

Schematic drawing of class 2601

Die Lokomotive, December 1904

The locomotives were basically used on main routes without significant gradients. There they typically hauled express trains weighing between 200 and 250 long tons and could reach speeds of 90 mph. Some of them were also used in front of trains with 350 long tons and proved their worth there, as long as there were no difficult adhesion conditions. Later, when they could no longer cope with the increased train weights, they were still used as pilot locomotives, sometimes even in front of coal trains. Their service life ended in the late twenties.

Superintendent L.B. Paxson of the Philadelphia & Reading was convinced in the mid-1890s that an express locomotive with one powered axle would still be sufficient to haul express trains at high speed. He was thinking in particular of some trains between Jersey City and Philadelphia that covered the 90 miles with a light load. When asked about the ideal wheel arrangement, the choice fell on 4-2-2, which was popular in Great Britain and was called “single” or “bicycle” there.

No. 385

Railway and Locomotive Engineering, August 1895

A Wootten firebox with a grate of 75 square feet was installed in order to be able to produce a lot of steam at high speeds with the combustion of residues from the anthracite processing. This meant that it was designed as a Camelback locomotive with the driver's cab in the middle of the boiler. The steam dome sat behind the driver's cab on the firebox. The power was provided by a four-cylinder compound engine of the Vauclain type, in which a jointly cast high and low pressure cylinder were present on each side.

Schematic drawing after the rebuild as 4-4-0

Die Lokomotive, July 1914

After the number 385 built in 1895, the almost identical number 378 followed in the following year. The locomotives ran the mentioned route including the intermediate stops at an average of 51.4 mph and ran very smoothly. The 385 is said to have even reached 120 mph for a short time. Even if the two locomotives easily transported trains of around 350 tons, the low adhesive weight was soon no longer sufficient.

Both examples were rebuilt in 1904 into locomotives with a 4-4-0 wheel arrangement, which differed from each other. One thing they had in common, however, was that both received a simple two-cylinder engine with 19 by 26-inch cylinders. The 385 became the D10-a class and retained its 84.25 inch coupled wheel diameter. It lost its combustion chamber during the rebuild and instead had a larger tubular heating surface. The 378, now class D10-b, had the coupled wheels downsized to 78.5 inches and still had a combustion chamber, but also had a slightly larger boiler overall.