In 1804, the Cornish engineer, Richard Trevithick built a steam loco for the Pen y Darren tramway in South Wales. As a tramway engine, it depended on the 'L' shaped plates of the track for guidance, not flanged wheels and edge rails as later railways favoured. The wheels, therefore, were not flanged. The loco was successful, but was really too heavy for the cast iron plates of the tramway, and it broke many of them. Nevertheless, this was the start of the steam locomotive.

Unlike some early engines the original did not survive, which is a pity as many countries have preserved some of their earliest examples of steam locomotives. However, this replica was built for the Welsh Industrial and Maritime Museum in 1981 and was as true to the original as the available information could make it.

In 2004 it was returned to working order in a very comprehensive restoration at the National Railway Museum in York in connection with the Railfest of that year to celebrate 200 years of the steam locomotive. So that it could operate at the York exhibition site, it was converted to flanged wheels as shown in the photo. The 'Penydarren' cast nameplate in the foreground was one that was carried by a modern diesel in recognition of the significance of the date