Train services between Birmingham, Rugby, Long Buckby and Northampton have been disrupted this morning.
The issue has been caused by an overhead wire damaged near Daventry
A spokeswoman for London Midland said: “Network Rail engineers are on site carrying out investigations. We will know more following this.”
Road transport is in place between Rugby, Long Buckby, Northampton and vice-versa using minibuses and coaches.
London Midland tickets are being accepted by Virgin Trains and Chiltern Railway at points between the West Midlands and London.
London Midland tickets can also be used on East Midlands Trains services between Wellingborough (coaches to and from Northampton) and St.Pancras.
And they can also be used on National Express West Midlands buses routes 11a, 11c,14, 59, 91 & 900.
Journeys to/from Northampton and the West Midlands/North should be made via Milton Keynes to avoid the line closure.
Network Rail engineers were on site at 3am after reports of faulty electric wires. They have been repairing about 40 foot of cable that has been damaged.
Mark Killick, area director for Network Rail, said: “We were on site immediately after the damaged wire was reported. We are doing all we can to safely complete the repairs and reopen the railway as quickly as possible.
“We are in constant contact with the train operators to minimise the impact to passengers. I’d like to thank everyone affected for their patience while we fix this problem.”
Passengers are advised to check with their train operator for the latest information before travelling or at www.nationalrail.co.uk.
The cause of the damage to the overhead lines is not yet known.