Following Nationalisation of the railways in 1948, the new British Railways inherited numbers of large tank engines which were particularly useful for commuter and branch line services, and while the former LMS and GWR regions had a good supply, other regions did not. A building programme was instituted, with Robert Riddles in Brighton drawing up a new loco based on the LMS 2-6-4T, whose design traces back to Henry Fowler's 1927 tank. 155 locomotives were built between 1951 and 1956, mostly in Brighton with small batches in Derby and Doncaster.

Designated Standard Class 4 Tank, the locomotives were distributed throughout the network, except in the Western Region which still had a plentiful supply of ex-Great Western "Large Prairie" tanks. They became particularly associated with the London, Tilbury & Southend line, until it was electrified in 1962, and with Glasgow's suburban services. Four were allocated to the Whitby depot in 1955 - three of them brand-new - but with the arrival of Diesel Multiple-Units to take over local services, they departed again between 1956 and 1958.

80135 was built in Brighton in 1956, and initially assigned to Plaistow and working the Tilbury line alongside her sister 80136. In 1962 a change in scenery beckoned and she left for Shrewsbury, and worked in Shropshire and Mid-Wales until her withdrawal in 1965, less than ten years after being built.

Consigned to Woodham Brothers' scrapyard in Barry Island, she was identified early for purchase by the newly-formed NYMR Trust in 1973, but with limited means nothing could be done with her until she was sold on in 1977 to Dutch businessman and rail enthusiast Jos de Crau, who funded her restoration. Returning to the rails in 1980, 80135 was painted at de Crau's request in BR Brunswick Green - the express passenger livery was never carried by any Standard 4 Tank in service, but what's the point in owning a steam locomotive if you can't choose the colour? (Rumours that he had to be talked out of LMS Red have been heard!) When Jos de Crau died in 2006, his locomotives and coaches were bequeathed to the railway, and we have kept on his idiosyncratic colouring as a mark of respect.