The line was declared to conform to the standard C1 loading gauge on 14 March. The first passenger carrying train comprising C1 stock to use the line was a railtour on 15 March hauled by 50 025 "Invincible". It was organised by the Southern Electric Group and ran from Paddington to . A preview service of electric trains ran on 27 April 1986 and the full timetabled service commenced on 12 May 1986. The next day, a wrong-side failure occurred involving three signals between Tonbridge and Hastings. Contractors had made errors in the wiring of the signal heads. With the inauguration of electric services, a half-hourly service was operated, with trains departing from Charing Cross at 15 and 45 minutes past the hour. Those departing at xx:15 called at , Sevenoaks, Tonbridge, High Brooms, Tunbridge Wells, Wadhurst, Battle, St Leonards Warrior Square and Hastings, taking 84 minutes. Those departing at xx:45 called at Waterloo East, London Bridge, Orpington, Sevenoaks, , Tonbridge and then all stations to Hastings, taking 99 minutes. The Royal Train visited the line on 6 May, conveying Queen Elizabeth the Queen Mother. It was stabled at Wadhurst whilst she ate lunch. The train was hauled by a Class 73 diesel-electric locomotive. Upon electrification, services were operated by 4CEP, 4CIG and 4VEP electric multiple units.