They struck near the level crossing at Owen Street, Tipton. As a result the signals were knocked out on that stretch of line. A spokesman for British Transport Police said: "We got a call at about 11.45pm and we have been on scene overnight.
"Scenes of crime officers have also been there to carry out a forensic examination.
"As a result of the theft and the closure of the line rail services have been hit and trains have either been cancelled, or are being diverted around the affected line."
He said how the diversions were being managed was a matter for the rail service providers.
* Anyone with information, or who may have spotted anything suspicious around Owen Street, can ring 0800 40 50 40.
