Etched brass kit. GWR Diagram S18 In 1887 the G.W.R. built thirteen sets of close coupled four wheelers to the designs of William Holden. They were for the Middle Circle services and had distinctive round topped doors to allow them to run over the Metropolitan Railway. When they were superceded on London suburban workings they spread to branch lines all over the system. Many ended their days in the 1940's in the Welsh Valleys. Recommended wheels, 1 pack Roxey Mouldings 7W003P 3ft 7in Mansell Coach Disc. Recommended couplings PC609 Premier Components Screw Link Couplings.