Thameslink has confirmed that a number of incidents between Blackfriars and St Albans are causing major disruption to their network.
Train services will be severely delayed, cancelled or revised, and it is expected that disruption will continue until around 8pm.
Power supply and signalling problems at Farringdon and St Albans are causing the disruption, and the operator is telling passengers to only travel is essential and to use an alternative route if possible,
Additionally, the operator has told passengers to travel to Luton or Gatwick Airport as soon as possible to make sure they make flights.
The latest travel advice can be found here.
Rail Replacement Buses have been sent to major stations between Peterborough and Hitchin, and between Bedford and Elstree & Borehamwood.
Network Rail are currently investigating a complex issue at Farringdon and due to the defect, a number of trains have been stopped at Farringdon, and are waiting for electric supply to become available.
This caused long delays through London during peak hours.
The signalling issue at St Albans is being fixed by Network Rail, but it affected two lines towards London and one of the northbound lines.
This disruption has led to most Thameslink trains and train crews being in the wrong place, meaning it is impossible to run according to the timetable.
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