The film tells the story of the building of a new generation of high speed Inter-City trains. As well as providing speed and air-conditioned comfort, the design philosophy behind the trains was to extend the modular replacement concept as far as possible. Complete engines, alternators, cooling and brake systems, and electronic controls had to be modified so that they could be disconnected quickly and replaced, thus allowing fast, easy maintenance with a high degree of reliability. The film was made for the equipment manufacturers and British Rail.