The route forms a major commuter route into London from Hertfordshire, Cambridgeshire and eastern Bedfordshire; ridership has grown rapidly over recent years. In 2009 rolling stock was transferred from other lines to allow additional services and longer trains to be run. By 2018 the line will be connected with the Thameslink route via a junction just south of the High Speed 1 bridge, north of Kings Cross, to allow through services to south of London.