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.

80136 was built in Brighton in 1956, and initially assigned to Plaistow and working the Tilbury line. 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. Like so many locomotives, she sat in Woodham Brothers' scrapyard on Barry Island until 1979. Rescued by Philip Oldfield, she became a labour of love, painstakingly and slowly restored with parts often built from scratch, and based at the Churnet Valley Railway. She first steamed in 1998 and worked at the Churnet Valley and then the Llangollen railway until her boiler ticket expired in 2008.

As with so many locomotives, she then had to wait her turn with work being done on an ad-hoc basis but in 2016 an agreement was reached with the owners to bring her to the NYMR to join her sister loco 80135. With most of the required work having been completed, she arrived in April as a separate boiler and frames, and the Motive Power Depot team at Grosmont reassembled her in record time, with just a month elapsing between remounting the boiler and passing inspection. She returned to regular service in August 2016.