The genesis of 25kv overhead electrification began in the late 1960s on the West Coast Main Line, the 1980s for the East Anglian Main Line, and the East Coast Main Line in the late 1980s. Development took place in stages culminating in fully electrified lines from London to Scotland on both East and West Coast lines, and from London to Norwich. The introduction of these lines required the construction of new motive power. Initially five types...