Travellers are facing disruption on Thameslink services (Image: Archant)
Faults with the signalling system between St Albans and Luton caused delays for commuters.
All lines were blocked between St Albans and Luton early in the morning on Friday, May 19 due to faults with the signalling system.
Thameslink advised commuters that they could use their tickets on London buses, on the London Underground and on other train services.
The lines were open by about 7.30am, but the service is still experiencing delays and disruption.
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