Trains travelling through Landywood were forced to run at reduced speed on all lines, with delays of up to 10 minutes, after trespassers were seen nearby.
British Transport Police were called to the scene after being alerted around 6.13pm by West Midlands Trains.
The scene was made clear and normal service was resumed by 6.45pm.
A spokesman for British Transport Police said: "We were called to the scene at Landywood Rail Station after receiving a call about trespassers on the line.
"An officer attended the scene and helped clear the line, with normal service back up at 6.45pm".