During the twenty years in which Britain's nationalized railway operated mainline steam locomotives, a vast array of individual designs complemented the British Railways 'Standard' machines, built up to 1960. Such was the variety of motive power to be seen on the network that this 'early' period of BR's existence has proved to be the most enduring amongst enthusiasts and modellers. The ready-to-run market has reflected this popularity in terms of models and liveries available off-the-shelf.