The earlier faulty train at Stevenage has now been moved, allowing all lines at this station to reopen.
As service recovers, trains may still be delayed by up to 20 minutes or revised.
This issue is expected to continue to impact services until 11:30.
Great Northern / Thameslink customer advice:
Delays are possible to services running in both directions through the Stevenage area, due to a fault on a train.
Some services may be subject to alterations as a result, meaning services may have cancelled stops or will terminate and restart at a different station to normal.
Journeys will take around 10-20 minutes longer than usual, so please allow extra time.
Planning your journey:
You can check train departures from your station here:
You can view live maps of the network here:
You can see the alternative route guides here:
You can also use our apps to find up-to-date information.
Can you tell me more about the incident?
There is a fault on a train, and this is now causing delays to other services travelling through this area.
Normally, when a fault on a train occurs, crews will gather details and report this to Fleet teams. If possible, the defect will be fixed promptly, and the train will get on the way. The 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 routes. Once they are on site, they will then monitor progress updates and ensure that the railway can be reopened as promptly as possible.
Until the defective train can be moved, teams will try to find a way to get other trains around the issue. This depends 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 our major routes, but not always. Network Rail's controllers will work to decide how many more trains can be sent through the area, and if this isn't possible, they will 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.