The County class of the GWR was developed by Hawksworth during World War II and was intended for mixed service. It was the last of a series of ten-wheelers begun by Churchward in 1902 with the Saint class. It included some innovations such as 280 psi boiler pressure and dual chimneys. However, the pressure was later reduced to 250 psi to save on maintenance costs, and later examples had single chimneys. Special optical features for GWR locomotives were the continuous splashers over all coupled axles and straight nameplates.

After two batches and 30 locomotives, production was discontinued as the staff evidently preferred the locomotives from Hawksworth's predecessor, Collett, and there was no need for more. The County class was retired between 1962 and 1964. Although not a single locomotive has survived, number 1014 “County of Glamorgan” is currently being built new.

After the GWR had taken over the Cambrian Railways, they needed modern locomotives for passenger services on these lines which only allowed a low axle load. Since there were none of these locomotives available, they decided to mount the superheated boiler of Duke class No. 3265 “Tre Pol and Pen” to the intact frames of Bulldog class No. 3365 “Charles Grey Mott” in 1929. This prototype retained the number and name of the Duke.

Because this prototype was successful, 29 further locomotives were built in the same way between 1936 and 1939. They got numbers from 3200 onwards and were officially called “Earl” class. Due to their origin being a mix of the Duke and Bulldog classes, they were also called “Dukedog”. The only one that has been preserved is No. 9017 “Earl of Berkeley”, which hasn't been operational since 2011.

After the First World War, George Churchward had already designed an express locomotive that was intended to complement and surpass his Star class. It was to receive the GWR standard boiler number 7, which was already used on the class 4700 2-8-0 express goods locomotive. However, this plan could not be implemented as it would have exceeded the permitted axle load of 20 long tons. 

Only his successor, Charles Benjamin Collett, designed the Castle class in the 1920s. The standard boiler number 8 was developed for this, which was lighter with increased size and had a larger grate area. It was tapered towards the front and had no dome. The associated locomotive was based on the Star class and had an extended frame with the same wheel diameter. This meant that the longer Belpaire firebox could be better accommodated and a larger driver's cab with side windows could now be used. In view of the larger boiler output, the diameter of the four cylinders was increased by one inch.

Schematic drawing with dimensions

Locomotive Magazine, September 1923

They replaced the Star class in use in front of the heavier express trains and were able to maintain high average speeds thanks to their 80.5-inch wheels and high boiler output. Shortly after they were put into service, they had competition from the even more powerful King class, which, however, was not as fast due to the smaller wheels. Thus, the heaviest express trains were pulled by the King class, while the Castle class got the faster trains that weren't quite as heavy.

The Castle class was considered Britain's most powerful express locomotive at the time of its introduction, although Gresley's A3 at the LMS was larger and also claimed that title. In comparison runs in 1924, however, the Castle class was able to win in the areas of tractive effort, average speed and fuel consumption. The Cheltenham Flyer, which weighed only 180 long tons, was able to cover the 77.25 mile-long route in 1932 at an average of 81.68 mph. The top speed reached 89 mph. 

Locomotive Magazine, September 1923

Over a long period from 1923 to 1950, 155 Castle class locomotives were built. A further 16 examples were created from the conversion of other locomotives. In addition to some examples of the Star class, this also included the Pacific “The Great Bear”, which was unsuccessful and was therefore converted back into a 4-6-0. Most machines were named after castles, but with a few exceptions.

The number 5005 “Manorbier Castle” was streamlined in 1935 and reached 100 mph. However, since this hardly brought any advantages in everyday life, the paneling was soon removed again. Later modifications to the production machines included a higher degree of superheating and, in some cases, a double chimney. In this way, No. 7018 “Drysllwyn Castle” reached a speed of 102 mph in 1958. Eight pieces are still preserved today, six of which had been operational at one point in time. In 2019, only one of these was still operational, while four others were currently being refurbished.

From 1927, the then chief engineer of the GWR, Charles Collett, procured 100 pieces of an improved version of the Class 4500 developed by Churchward. The most important difference concerned larger water tanks, which could be visually recognized by the sloping top at the front. Since the company numbers of the first series followed the 75 units of class 4500 without gaps, they became class 4575. The total of 100 units were initially assigned numbers up to 4599 and finally from 5500 to 5574.

Although these locomotives were built later than their predecessors, they remained in service little longer. Their retirement began in April 1956 and was completed in December 1964. A total of eleven pieces still exist today. The number 5521 even came to Poland from 2007 to take part in the annual parade of the museum in Wolsztyn. After that it spent some time in Hungary to pull the Orient Express and after another stay in Poland to come back to England.

Collett had a revised version of the earlier 5100 class procured from 1929. Since the class 5100 locomotives had the numbers 5111 to 5149 in addition to the number 5100, the first examples were given the numbers 5101 to 5110. The others were given numbers between 5150 and 5199 and between 4100 and 4179. There were a total of 140 examples were made, of which the last ten only left the factory in Swindon in 1949.

In the general dimensions, the locomotives corresponded to their predecessors, but they were a bit heavier and received various improvements in detail. The class 5101 engines were visually recognizable primarily by the external steam lines between the cylinders and the boiler and the rounded step between the running boards and the buffer beam. The larger coal bunker could be seen at the rear end of the locomotive, which the class 3150 also had.

Although the last order was not placed until after British Railways was formed, traffic on the branch lines on which the Class 5101 could operate soon diminished. As a result, fewer and fewer engines were needed for passenger service and some were used to push or pull trains on inclines. They were used, for example, on the steep routes in Devon or around the Severn Tunnel. After the last engines were retired in 1965, a total of ten engines were preserved for posterity. Five of them have so far been refurbished and made operational again.

The GWR class 5205 was a class of 2-8-0T tank locomotives designed by Charles Collett for coal traffic on the short, but steep lines from the coal mines in South Wales to the ports. It was based on Churchward's class 4200 that had been used since 1910 in the same role. The new class was generally very similar, but had cylinders whose diameter was half an inch bigger.

Between 1923 and 1926, 70 had been built at Swindon which got the numbers 5205 to 5274. In 1930, numbers 5275 to 5294 followed and since they had curved instead of straight frames, they were designated as class 5275. Between 1934 and 1936, 20 locomotives of class 5205 and all 20 of class 5275 were rebuilt to the 2-8-2T class 7200.

Since the numbers from 5255 had been freed due to the rebuilds, ten more locomotives of class 5275 were built in 1940 and numbered 5255 to 5264. Most locomotives of these classes were withdrawn between 1961 and 1965. Three are still existing, with 5239 “Goliath” being operational at the Dartmouth Steam Railway and 5224 in store since 2011.

The first class of tank locomotives that the GWR had built from the beginning as “Pannier Tanks” was the class 5700. Shortly after this came the lighter class 5400. The special shape of the water tanks got its name from the panniers which were used by pack animals. These were easier to adapt to the Belpaire firebox compared to a saddle tank and resulted in a lower center of gravity.

The class 5700 came from Collett and was based on the class 2721 locomotives, which were later rebuilt into Pannier Tanks. A total of 863 were built between 1929 and 1950, making them the most numerous class of the GWR and thus became an icon. Some adapted variants were designated the classes 6700, 8750 and 9700. Due to the high number of locomotives, other number ranges also had to be used, such as the number 3738 shown in the photo.

Although heavier than the class 5400, the class 5700 could also be used on 70 percent of the GWR route network. Since the hammer blow was comparatively light, they were later able to operate on 90 percent of the network due to a reassessment of the axle load class. It was used not only as a freight and shunting locomotive, but also regularly as a passenger locomotive. Their retirement took place between 1956 and 1966.

Charles Benjamin Collett, GWR's chief engineer since 1922, soon had the task of developing a more powerful express locomotive than the Castle class of its predecessor Churchward. The goal was to achieve a starting tractive effort of 40,000 pounds, despite the high speeds. First, the question of the ideal wheel arrangement had to be examined.

While the Pacific had long established itself as the ultimate express locomotive on the European mainland, the ten-wheeler remained largely the choice in Great Britain. Although the GWR had already built a single Pacific in 1908 with “The Great Bear”, this design was considered prone to slipping. After all, only half of the axles on the Pacific were powered, compared to 60 percent on the Ten-wheeler. So the choice fell again on a ten-wheeler, but with an axle load of 22 and a half tons.

Much of the power increase over the Castle class was achieved by increasing the boiler pressure to 250 psi. The boiler was introduced as GWR standard design no. 12, but only used on the King class. With a tube length of only 16 feet, it no longer reached the excessive length of “The Great Bear” and was able to achieve greater power using high quality coal from South Wales.

In addition, the stroke of the four cylinders has been increased by two inches and the diameter of the coupled wheels has been reduced by 2.5 inches to a still adequate 6 feet 6 inches. Since the required 40,000 pounds of starting tractive effort could not quite be achieved, the cylinder diameter was increased by a quarter of an inch.

No. 6001 “King George V”

Railway and Locomotive Engineering, July 1927

Initially, the new class was to be named after cathedrals. However, when number 6000 was brought to the United States for the Baltimore & Ohio Jubilee celebrations in 1927, it was christened “King George V” after the current regent. As a result, all other engines were named after British kings. After a total of 20 production engines that had been manufactured in 1927 and 1928, another ten followed in 1930. After No. 6007 “King William III” was destroyed in an accident in 1936, a new loco of the same number and name was built using some of the assemblies that were still intact.

The King class was used in front of the main express trains of the GWR, which ran west towards Cornwall and sometimes consisted of more than 13 cars. A second locomotive only had to help on the steep inclines in Devon. From Plymouth at the latest, however, another locomotive had to be used for the rest of the route through Cornwall, since the axle load of the King class was too high for the Royal Albert Bridge. It also turned out that the outer cylinders with a diameter of 16.25 inches were too wide for the loading gauge in some places, so that they later had to be converted to 16 inches.

The later modifications to individual pieces were limited. For example, in 1935, road number 6014 “King Henry VII” was partially streamlined. Only the superheaters were replaced by a different design from 1947 onwards. When the locomotives were distributed to other parts of the country when British Railways was founded in 1948, it turned out that they showed a noticeable loss of power elsewhere with less energetic coal. At the end of the 1950s they were still equipped with a double induced draft system, but they were all phased out by 1962.

Although the 70 examples were only built between 1931 and 1935, the class 6100 was the direct successor to the class 5101 built up to 1949. It was developed specifically for use in the London area as a replacement for the class 2221 4-4-2T tank locomotives built from 1905 onwards. In general dimensions and coupling wheel diameters, these locomotives were still the same as the 1903 class 5100 and the cylinders had the smaller 5101 cylinder diameter of 18 inches. With the boiler pressure increased to 225 psi, the starting tractive effort was increased by around 12.5 percent despite the reduced heating surface.

For use on the suburban platforms in London-Paddington, some locomotives were fitted with mechanical train stop, which opened a valve when passing a stop signal and thus triggered emergency braking. The typical area of application ranged from north-west London to Aylesbury, which corresponded to a distance of around 40 miles. Even after the founding of British Railways, the engines remained indispensable, but they soon faced strong competition in the form of the first generation of diesel railcars. Although their status fell as a result, the last examples were able to hold their ground in service until 1965.

No. 6866 “Morfa Grange” in front of No. 6824 “Ashley Grange” at Southall Depot in November 1962

Ben Brooksbank

Locomotive Magazine, October 1936

As early as in 1901, Churchward's program of standard locomotives for the GWR included a two-cylinder 4-6-0 mixed traffic class. For the time being, this was not built and ten years later, the 2-6-0 class 4300 was built for similar duties. Only Collett actually built the mixed-traffic 4-6-0s, starting with the Hall class in 1924. While this had driving wheels with a diameter of six feet, the Grange class shown here had a diameter of only five feet and eight inches to increase pulling power, with the cylinder dimensions remaining the same.

To replace the class 4300, a total of 80 were built between 1936 and 1939 and named after granges in the GWR area. Hence the wheels, valve motions and tenders of withdrawn class 4300 locomotives were re-used. Since the axle load of the Grange class was somewhat higher than that of the 4300, they could not be used on all lines. This prompted Collett to build the Manor class as a lighter variant. All Grange class locomotives were withdrawn and scrapped between 1960 and 1965. In 1998, construction of No. 6880 “Betton Grange” was started. It was steamed up for the first time on April 11, 2024.