Whilst the railroads were originally developed as a means primarily of moving raw materials and freight between source and customer, it was not before passenger traffic was also considered to be an additional source of revenue. One of the most dramatic shifts in the railway industry in the years since Nationalization is the shift away from freight, as road haulage became more dominant, and the increasing dominance of passenger traffic. Whilst, in the early 21st century, freight traffic is but a fraction of that achieved in the 1950s, passenger traffic has reached levels not seen since the years before the Beeching Axe fell and when the network was significantly larger. In 1948, British railroads inherited myriad coaches from the 'Big Four' companies; from the early 1950s, standardization was imposed with, initially, the Mark 1 design to be further developed as Mark 2 and Mark 3 models from the early 1960s onwards. From the mid-1970s onwards, locomotive-hauled stock was gradually withdrawn in favor of HSTs, used nationwide, and the InterCity 225s designed for use on the electrified East Coast main line.