Teams carrying out excavation work near to Apperley Bridge train station in the Bradford district made the dramatic discovery this morning (Tuesday) and all services between Leeds and Shipley were cancelled.
A spokesperson for British Transport Police said: "British Transport Police were called to Apperley Bridge Railway Station just before 9.30am today (February 27) to reports of an unexploded ordinance found near the station during excavation work taking place."
A 100m cordon was put in place around the scene and police and ambulance crews were present to "ensure the safety of those in the area".
British Transport Police said that a Explosive Ordnance Disposal team from the British Army "and confirmed the ordinance is a solid metal shell (that) poses no threat to the public".
The cordon was lifted at around 12.30pm.
The below gallery features a selection of pictures from the scene.