A fault with the signalling system between Stansted Airport / Royston and Cambridge means that trains have to run at a reduced speed on some lines. Trains running between these stations may be cancelled, delayed by up to 30 minutes or revised.
Disruption is expected until 15:30.
Customer Advice
Greater Anglia
Trains have to run at a reduced, cautionary speed from Shelford to Cambridge, in order to ensure the safe operation of the Railway.
Network Rail staff are on site and investigating the fault.
Great Northern / Thameslink
The service between Letchworth Garden City and Cambridge is disrupted until further notice, with fewer trains running through.
Please allow an extra 30 minutes to complete your journey as there are delays to services that are running through, and you may have to change trains more often than usual.
You should check station screens and planners for the latest information.
Planning your journey:
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Ticket acceptance
Your ticket will be accepted mutually on both Thameslink and Great Northern trains between Stevenage and Cambridge.
Can you tell me more about the incident?
A number of track circuit failures will disrupt your journey in the Shepreth area.
This part of the network uses track circuits to detect the position of trains. These are electrical systems which monitor whether a train is on a section of track. They operate as part of the signalling system, which is designed to be "fail safe".
When a track circuit fails, the signalling system will interpret this as a train remaining in place, even though there may not be a train present at all, or the previous service may have long since left the area.
As a result, further trains cannot be automatically allowed onto the relevant section of track. Train drivers will be stopped by red signals on approach. They will then get verbal permission from the signaller so that they can proceed, and will run at a heavily-reduced speed as far as the next signal. This is so that the drivers will stop safely if they see anything ahead of them.
In some areas, the sections between signals can be several miles long, so this can result in delays building up. Even with shorter sections of track affected, there would still be a delay of at least a few minutes to each journey.
Track circuit faults can be caused by a number of different issues, including electronic faults or obstructions on the track. Network Rail manage the signalling system, including track circuits, and their staff will be investigating as quickly as possible.
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.