A broken down train at Harpenden is causing delays of currently about 15minutes on the southbound Thameslink line (April 11).
According to the National Rail website, disruption and alternations between Bedford and Brighton are expected until 9.15am.
The train in question is having power problems, but the driver is talking to technicians to resolve the issue.
Once it is cleared from the tracks the service should go back to normal, it says online.
For more information, click here.
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