A fault with the signalling system at Stevenage means that trains have to run at a reduced speed on all lines northbound lines. Trains running through this station may be delayed by up to 30 minutes.
Disruption is expected until 19:30.
Customer Advice
Great Northern / Thameslink
Please allow extra time to travel this afternoon as a signalling issue is causing delays of up to 20 minutes to trains running through towards Hitchin.
This will affect services to Peterborough, Cambridge and Kings Lynn, and stations in between.
Ticket acceptance
Your ticket will be accepted mutually between Great Northern and Thameslink services between Finsbury Park and Cambridge.
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Can you tell me more about the incident
An axle counter failure is disrupting trains which travel from Stevenage towards Hitchin.
This part of the network uses axle counters to detect whether trains are in the area. These are electrical systems which check the passage of train wheels and 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 an axle counter 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.
Axle counter faults can be caused by a number of different issues, including electronic faults and debris coming into contact with them. Network Rail manage the signalling system, including axle counters, and their staff will be investigating as quickly as possible. We're closely monitoring progress updates.
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.