Services between Basingstoke, Woking, Hampton Court, Alton, Guildford and London Waterloo have been disrupted due to a tree blocking the line at Walton-on-Thames.
Major disruption is expected until the end of the day, with services between Woking and Surbiton either cancelled, revised or delayed.
Teams attended the site to try to remove the branches; however, they were larger than expected and could not be fully cleared.
Tickets can be used at no extra cost on a range of other services. Ticket acceptance can be checked with South Western Railway.
Journeys can also be checked online to see when the disruption clears.
