Rush hour commuters are facing delays after reports of a trespasser on the line between Linlithgow and Falkirk.
Services have been halted in the meantime.
ScotRail is encouraging passengers to use services to/from Queen Street Low Level or Glasgow Central if they are travelling between Edinburgh and Glasgow in either direction.
There are reports of passengers being asked to leave a train at Polmont.
ScotRail has said it is trying to get replacement buses for passengers at the following stations: Linlithgow, Bathgate, Falkirk High, Falkirk Grahamston, Dunblane and Haymarket.