The name "Chiltern Line" was invented as a marketing name for the line by Network SouthEast in 1985, in reference to the Chiltern Hills which the route passes through near its southern end. The route was originally part of the Great Western Railway's main line from London Paddington to Birmingham Snow Hill, and . Most main line services between London and Birmingham on this route were discontinued in 1967 after the West Coast Main Line was electrified, and Snow Hill station was closed. Services were resumed between London and the reopened Snow Hill in 1993, however they were routed into Marylebone, formerly the London terminus of the now-closed Great Central Main Line, instead of the historic terminus at Paddington.