Commuters have been warned by London Midland to expect delays and changes to the service tonight after a series of incidents including vandalism and fire damage.
Trains affected are between Northampton and Birmingham New Street.
A spokesperson said: “Due to vandalism and fire damage to signalling cables, there is a reduced service on the line this evening.
“Trains will leave Northampton at 16 minutes past the hour calling all stations to Birmingham New St. The return service will leave Birmingham New St at 33 minutes past the hour.
“In addition, the Birmingham New St to Birmingham International service will also call at Marston Green.”