In the search for a modern generation of express locomotives for the GWR, Churchward, who had been appointed chief engineer in 1902, undertook a number of trials. The result of this process was the Saint class, which formed the basis for the GWR's further two-cylinder 4-6-0s. These were the classes named Hall, Modified Hall, Grange, Manor and County, with the County class only appearing in 1945.

It started with three prototypes from 1902 and 1903, all of which had the 4-6-0 wheel arrangement and two cylinders, but differed in some details. They were also compared with a French De Glehn compound Atlantic, so one of them was also rebuilt into an Atlantic. A key factor turned out to be that the ports of the valves had to be significantly enlarged compared to the usual dimensions at the time in order to be able to supply sufficient steam for large cylinders. This led to the building of the first production machines in 1905.

These were mostly named after characters in Sir Walter Scott's novels and consisted of six Ten-Wheelers and 13 Atlantics. They had a tapered boiler with no superheater but with a high boiler pressure of 225 psi or 15.5 bars. Since Churchward appreciated the additional tractive power of the Ten-Wheelers, the Atlantics were also rebuilt into Ten-Wheelers.

In 1906 ten more locomotives were built, which were referred to as “Lady class” because of their names. Among them there were differences in the length of the firebox and the tubes in the boiler. No. 2901 “Lady Superior” was built with a modern Schmidt superheater, while the others received a Swindon No. 3 superheater between 1909 and 1911. The 2903 “Lady of Lyons” is said to have reached a speed of 120 mph or 193 km/h running light on a slight down gradient of 1 in 300 in 1906, but this must be doubted due to the inaccurate measurement methods.

No. 181 “Ivanhoe” in its original form als Atlantic

GWR

In 1907 the 20 locomotives of the actual Saint class were built. These were also soon retrofitted with superheaters. From 1911 onwards, 25 Court class locomotives followed, which were the first to have a superheater from the start and whose cylinders were half an inch larger. Here, too, there were small differences in the boilers between the individual locomotives.

After the Castle class took over the fastest express trains, the Saint was also used in front of express freight trains. Since the wheel diameter of 6 ft 8 1/2 in or 2,045 mm was not very suitable, Collett developed the Hall class with smaller wheels. The prototype was created by rebuilding the 2925 “Saint Martin” with six-foot wheels.

The Saint class is considered groundbreaking not only because of its successors at the GWR, it also generally set standards for further development. They were decommissioned between 1931 and 1953. Since no member of the Saint class remained, the Hall class's descent from it was remembered. So No. 4942 “Maindy Hall” was rebuilt into 2999 “Lady of Legend” between 1995 and 2019.