Before the war, 14 and 15 ton all-steel mineral wagons had been built by Charles Roberts and the Butterly Company as replacements for wooden coal wagons. Some were bought by private owners but, along with the rest, they were requisitioned by the government on the outbreak of war. During the war, the Ministry of Transport (MoT) started ordering 16T steel wagons and some 60,000 of these were taken into BR stock in 1948.

British Railways had around a quarter of a million steel mineral wagons. These took over the work of the ageing 7-plank wagons, dominating coal, stone and iron ore transportation in the '50s and '60s. The standard design of all standard designs was the ubiquitous 16 ton all-steel end door mineral wagon, built for British Railways in their tens of thousands throughout the 1950s. The building of them finished in 1959.

One particularly common version had an opening flap above the side doors, known as a 'London Traders' flap. There are conflicting ideas about its function but it is generally thought to have been provided to make it easier for coal merchants to unload the wagon by hand.