engine probably influenced to a large extent the use made of engines of the 4-6-0 type". No.100 was renumbered 2900 in 1912, and was withdrawn from service in 1932. No. 98 A second prototype locomotive, No. 98, was built at Swindon Works in March 1903 (Lot 138) to a similar design but with a taper boiler, re-designed valve gear layout and cylinders and a shorter wheelbase. Valve diameters were increased from to . According to Poultney, these improvements "may truly be said to be the keystone of the arch upon which all modern locomotives are designed". In 1906 this locomotive was re-boilered with a boiler to correspond with the third prototype. This prototype locomotive was named Vanguard in 1907 (renamed Ernest Cunard in the same year). It was renumbered 2998 in 1912, received a superheated boiler in 1911 and was withdrawn in 1933. No. 171 A third prototype, No. 171, was built at Swindon in December 1903 (Lot 145) incorporating the improvements to No. 98 but with a boiler and minor amendments to the heating surface and grate area. It was built as a 4-6-0 but in October 1904 it was converted to a 4-4-2 to enable better comparison with the performance of the French built de Glehn 4-4-2 Compound; it was reconverted to 4-6-0 in July 1907. The conversion was carried out by substituting trailing wheels with outside suspension for the final set of driving wheels. It was named Albion in 1904, renumbered 2971 in 1912, received a superheated boiler in 1910 and was withdrawn in 1946. No. 171 formed the basis of the main production series, introduced in 1905, although at this time Churchward was still unsure of the relative merits of the 4-4-2 and 4-6-0 wheel arrangements. Production series The Saint class appeared in four production series built between 1905 and 1913, each of which differed in dimensions. There were also differences between members of each series in terms of the boilers used, wheel arrangement, and arrangements for superheating. Different series and individual locomotives within series were also fitted with different tenders ranging from to capacity. Scott series Whilst 171 was undergoing trials in 1905 nine further locomotives were ordered to be built at Swindon Works to a similar design (Lot 154) followed by a further ten (Lot 158), totalling 19 locomotives in this series. Thirteen of these were built as 4-4-2s and six as 4-6-0s. However,