The 3571 Class was a class of ten 0-4-2T tank engines designed by George Armstrong

George Armstrong (engineer)

George Armstrong was in charge of standard gauge steam locomotives for the Great Western Railway at Stafford Road Works, Wolverhampton from 1864 to 1897...

 and built at the Wolverhampton Works of the Great Western Railway

Great Western Railway

The Great Western Railway was a British railway company that linked London with the south-west and west of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament in 1835 and ran its first trains in 1838...

 in 1895-7. The 3571s, numbered 3571-3580 and built as Lot No. C3, were in essence a continuation, and conclusion, of the series of 517 Class

GWR 517 Class

The 517 Class were small 0-4-2T tank engines designed by George Armstrong for local passenger work on the Great Western Railway. They were built at Wolverhampton Works and were outshopped between 1868 and 1885. They were built in thirteen lots commencing with 517–528 and ending with 1477–1488 in...

 built during Armstrong's long period of virtual autonomy at Wolverhampton. They differered from the 517s (apart from No. 1477 in rebuilt form) in that the outside frames were wider, constructed as a continuation of the valence under the running plate.

None of the 3571s was ever fitted for autotrain

GWR Autocoach

The GWR Autocoach is a type of coach that was used by the Great Western Railway for push-pull trains powered by a steam locomotive. The distinguishing design feature of an autocoach is the driving cab at one end, allowing the driver to control the train without needing to be located in the cab of...

 working. They spent most of their lives in the Chester and Birkenhead areas; all but two survived to the 1940s, and three into the British Railways era. The last was No. 3574, withdrawn in December 1949.

Source

• F. J. Tabor (1959), The Locomotives of the Great Western Railway, part six: Four-coupled Tank Engines, RCTS