Ages of Steam - The Jazz Age DVD In Great Britain, the Victorians built the vast bulk of the country s railway system and constructed steam locomotives to work them - many different designs were created, with many different results. The final form of the steam locomotive was seen in the designs introduced in the early years of the 20th century, from there on development was in detail and power. Using footage from the last quarter of a century, this programme looks at the way this final form was refined by some of the most famous engineers of their time, right up to the last steam locomotives built for main line service in the country. This is The Jazz Age, examining the locomotives of the 1920s.