Delays between London and Stevenage expected until 13:00 

Route(s) affected

Grand Central between London Kings Cross and Bradford Interchange / Sunderland

Great Northern between London Kings Cross and Letchworth Garden City / Cambridge / Kings Lynn, and also between Moorgate and Welwyn Garden City

Hull Trains between London Kings Cross and Hull / Beverley

LNER between London Kings Cross and Lincoln / Hull / Leeds / Bradford Forster Square / Skipton / Harrogate / York / Middlesbrough / Newcastle / Berwick-upon-Tweed / Edinburgh / Aberdeen / Inverness

Lumo between London Kings Cross and Newcastle / Edinburgh / Glasgow Queen Street

Thameslink between between Brighton and Cambridge, between Horsham and Peterborough, and also between Sevenoaks and Welwyn Garden City

Description

A fault with the signalling system between London and Stevenage means that trains have to run at a reduced speed on some lines. As a result, trains running between these stations may be delayed by up to 15 minutes.

Disruption is expected until 13:00.

Great Northern / Thameslink customer advice:

If you are travelling from Welwyn Garden City towards Hitchin you can travel on your normal route, but services will be disrupted.

You will need to allow at least an additional 15 minutes to complete your journey.

Please talk to station staff, look at the information boards or check your journey planner for the most recent information.

Can I use my ticket with another operator?

You can travel on the following services at no additional cost:

• Thameslink services between Welwyn Garden City and Hitchin

• Great Northern services between Welwyn Garden City and Hitchin

Please be aware that using alternative travel will add at least 20 minutes to your journey depending on the route.

Planning your journey with Thameslink:

For help planning your journey, check live departure boards, view a live network map or see alternative route guides.

Planning your journey with Great Northern:

For help planning your journey, check live departure boards, view a live network map or see alternative route guides.

If you’re travelling within London, you can use the TfL Journey Planner.

Stay up to date on the move with Thameslink's WhatsApp channel or Great Northern's WhatsApp channel. Live updates are available Monday to Friday, 07:00–21:00.

Can you tell me more about the incident?

There is a fault with the Train Protection and Warning System (TPWS), which is part of the signalling equipment. This is a safety system which monitors the speed of trains, and whether they have stopped correctly for red signals.

The TPWS system consists of electrical grids on the track which work with a sensor system underneath each train. In the case of speed restrictions, the system detects how long the train takes to pass between two fixed points. If this time is too short, it would mean the train has been travelling beyond the speed limit, and the grids will stop the train. For red signals, the grid adjacent to the signal will be switched on, and if a train passes the signal, it will also cause it to stop. These incidents are extremely rare, but every effort is taken to keep you safe during your journey.

In this case, the TPWS system is faulty, which means that other signals on approach to the fault will automatically be restricted, so drivers come to a stop before they get to the faulty equipment. Railway signalling works on "fail safe" principles. If there's a technical failure, the system should go into a more restrictive state, so that trains can be slowed or stopped in time.

However, this does mean that there will be some delays, as your trains can't travel as normal through the area. Network Rail are responsible for TPWS, as part of the signalling system, and they are attending as quickly as possible to resolve the problem.

Ticket flexibility:

If your train is cancelled, you will be able to travel on an alternative service operated by any other participating train company, either two hours before or two hours after the original departure time of the cancelled service, in order to reach your destination.

If you decide not to travel or cannot complete your journey due to cancellations, you are entitled to a full refund from your original point of sale.

For further information and guidance please contact your train company or speak to a member of railway staff.

Check before you travel:

You can check your journey using the National Rail 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.