London first appeared during the episode, Gordon's Promise where Gordon met and talked to Alice for the first time since his departure to Sodor in 1923. This is also where Alice's shed is located since her manager, Dave Matthews was worried about her volunteers, finance and the park for children in East Anglia talking to her. It ended with its appearance in Rescue Mission where Gordon rescued her and taken his train to the station only to meet Patrick telling him the directions to get to Alice's shed. Both Alice and Gordon left London near the end of the episode with his train to the works station at Crovan's Gate. Sir Stephen Topham Hatt actually was heading to the city for a meeting in the episode, A Stranger in Need, but he had to cut off the trip due to his daughter being in hospital after being run over in the right leg by a bad driver on Thomas' Branch Line.
With London being used for Pip and Emma to do passenger runs up to Knapford station, London was mentioned in one episode which was Cold Reception. The sponsor, the Royal Mutual Chartered Trust Bank is located within this city. One of their representatives, Jane Albworth, who was the sister of the late Sir Walter Albworth, traveled from London to Knapford station on one of their expresses. She boarded Duck's passenger train up to Arlesdale and got off there to meet the inhabitants of the railway. She took some interest into it and was later rescued by Olivia when Mrs. Albworth had missed her passenger train and spoke to the stationmaster about the emergency.