When steam railcars appeared in Great Britain in large numbers at the beginning of the century, James Manson of the G&SWR also followed the trend and had one steam railcar built in 1904. The vehicle consisted of a small, four-coupled tank locomotive and a conventional passenger carriage, which had only one bogie at the rear end. In theory the locomotive could have been detached from the carriage and used independently, however its water supplies were carried under the floor of the carriage.

The railcar was built in G&SWR's own workshops in Kilmarnock and was used on the nearby line between Mauchline and Catrine, which was only about three miles long. Two identical vehicles were ordered the following year. The use of the railcars ended in 1916 and in 1922 they were sold to the scrap dealer.

The Lancashire & Yorkshire Railway operated a total of 20 steam railmotors which were of two different types. The first two vehicles were of a design that had been built by Kerr, Stuart & Co. for the Taff Vale Railway and was also ordered for the L&YR by George Hughes in 1904. They consisted of a small 0-2-2 locomotive and a passenger car that was designed like a semi-trailer. The locomotives had a small transversely mounted boiler with a central firebox and one smokebox at each end. At the rear end, the trailers had an auxiliary cab and a luggage compartment. They only remained in service until 1909.

Kerr, Stuart type

Locomotive Magezine, August 1905

In 1906, Hughes introduced a more conventional type that was built a total of 18 times by 1911 in their own shops. The general layout was the same, but the locomotive part was more similar to a conventional tank locomotive. So they had a longitudinally mounted boiler and had both axles driven. All 18 came to the LMS in 1923 and the first ones were only withdrawn in 1927. The last one even formally passed to British Railways in 1948, but was only assigned its new number on paper and withdrawn in March.

South London commuter rail services, operated by the London, Brighton and South Coast Railway, were electrified from 1908 using overhead AC power. The implementation was carried out with 6,700 volts by the German AEG. As vehicles for these routes, three-car multiple units were ordered from the Metropolitan Carriage & Wagon Co. Ltd., now known as Metro-Cammell. Because of the competition from the new tram lines, only eight trains were ordered. Each initially consisted of two third-class railcars and a first-class intermediate car. All axles of the power cars were powered by an 115 hp motor.

Later, the trailers were removed and used in locomotive-hauled trains. At the same time, 14 mixed-class driving trailers were manufactured, each coupled to one of the power cars. The two additional power cars were provided as a reserve because they required more maintenance than the driving trailers. From 1928 the routes in south London were operated on 660 volts direct current from a conductor rail, similar to the current system. The Southern Railway, which had operated these routes since 1923, converted the vehicles for the DC system. These units, known as 2SL, each consisted of two former power cars, but only one bogie of one of the vehicles was powered. They were in use until 1954.

With the electrification of the suburban lines of the LSWR, a large number of electric multiple units was needed. Since this would free lots of four-car permanently coupled coaches which had been built to be drawn by steam locomotives, the most economic way was to rebuilt these. So a number of these four-car units, built between 1902 to 1912 were used to create 84 electric three-car units.

Each end car had a cab and baggage compartment at the end and below these was a powered bogie with two 275 hp traction motors. Power could only be controlled via a simple on-off switch that automatically switched through the resistors until full power was reached. Because of the switching sounds of this machinery, the trains earned the nickname “nutcrackers”.

Over the years, the units got modifications like new, longer frames. Some units were withdrawn in the late thirties, but others were used as basis for the construction of the four-car 4-SUB sets starting in 1941. Also some unrebuilt units survived until the founding of British Railways and were withdrawn around 1950.