Thameslink is a 68-station main-line route in the British railway system running 225 km (140 mi) north to south through London from Bedford to Brighton, serving both London Gatwick Airport and London Luton Airport, with a suburban loop serving Sutton, Mitcham and Wimbledon and a suburban line via Catford and Bromley South to Sevenoaks. It opened as a through service in 1988 and by 1998 was severely overcrowded, carrying more than 28,000 passengers in the morning peak.