The South Eastern Main Line is a major long-distance railway route in South East England, UK, one of the three main routes crossing the county of Kent, going via Sevenoaks, Tonbridge, Ashford and Folkestone to Dover. The other routes are the Chatham Main Line which runs along the north Kent coast to Ramsgate or Dover via Chatham and High Speed 1 which runs through the centre of Kent to the coast at Folkestone where it joins the Channel Tunnel.