Due to the communication alarm being activated on a train between Finsbury Park and Stevenage some lines are currently disrupted. As a result, trains may be delayed.
Disruption is expected until 20:45.
Customer advice:
You'll be able to see any further updates on this page, so please continue to check back here.
If you need to use another route, we'll let you know shortly.
Planning your journey:
You can see live maps of the network here:
These maps will show where your journey is likely to be affected.
You can also use the Great Northern and Thameslink apps to find up-to-date information.
Can you tell me more about the incident?
We've had a report of a fault on a train in the Potters Bar area, and this is now causing delays to other services travelling through this station.
Normally, when a fault on a train occurs, crews will gather details and report this to the Fleet teams. If possible, the defect will be fixed promptly, and they'll get the train on the way. Initial steps are designed to take around 10 minutes.
However, sometimes the fault cannot be fixed in this time frame. In this case, wherever possible, the train will be taken out of use and sent to a depot. This does take additional time, as the crew will need to make sure that everyone's managed to leave the train.
If this can't be done either, specialist engineers will be sent to site, known as "fitters". Fitters are based in key locations around the network, 24 hours a day, and they are able to attend anywhere on our routes. Once they are on-site, we'll then monitor progress updates and ensure that the railway can be reopened as promptly as possible.
Until the defective train can be moved, staff will try to find a way to get other trains around the issue. This depends on how many lines are available, and whether the signalling equipment is set up to allow trains to be routed around the problem. This is more often the case on major routes, but not always. They'll work with Network Rail's controllers to decide how many more trains can be sent through the area, and if this isn't possible, they'll see what alternative solutions are available to help you continue your journey.
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.