Delays between St Albans City and West Hampstead Thameslink expected until 11:00 

Route(s) affected

between St Albans City and Sutton (Surrey), between Bedford and Three Bridges / Brighton, and also between Luton and Rainham (Kent) / Orpington

Description

A fault with the signalling system in the Radlett area means that some lines towards London are disrupted. As a result, trains running between St Albans City and West Hampstead Thameslink will be delayed by up to 15 minutes.

Disruption is expected until 11:00.

Customer advice:

Some Thameslink services will be delayed in the Radlett area on the route towards London.

You can continue your journey as normal but please allow up to an additional 25 minutes to complete your journey.

Planning your journey:

You can use live departure boards, a live map of the network and the alternative route guide to help you.

If you're travelling in the London area, you can plan journeys on alternative routes by using the TfL Journey Planner.

The Thameslink app will also help you plan your journey.

Can you tell me more about the incident?

Trains are likely to have some delays due to a fault with a signal in the Radlett area. In this case, the signal is unable to show the normal coloured light indications to drivers, and instead, it's showing a red light. This means drivers have to stop at the signal and gain verbal instructions to continue. Your journey will unfortunately take longer as a result.

Railway signals are designed to warn drivers that they have to stop because the system can't yet confirm that the route ahead is clear. In most places, the signalling system will show a green light, or aspect, when the track is clear for a long distance ahead, and drivers will then be shown one or two yellow lights to warn them when they are approaching a red signal. This means that they can anticipate the amount of braking that's required to stop before they reach another train or any form of problem on the line.

Signalling runs on "fail safe" principles, so if the signals can't step through the usual colours, they will instead show a more restrictive colour - for example, red instead of green. This means drivers will have to stop, but in fact, the route ahead may still be clear. This leads to delays.

The signalling system is maintained by Network Rail, and Thameslink are working closely with them to diagnose the fault and make sure it is fixed as quickly as possible. Until this is done, they will be closely monitoring the train service and doing their best to keep to the timetable.

Check before you travel:

You can check your journey using the National Rail Enquiries real-time Journey Planner.

Compensation:

You may be entitled to compensation if you experience a delay in completing your journey today. Please keep your train ticket and make a note of your journey, as both will be required to support any claim.