Scores of trains in and out of Glasgow Central were delayed or scrapped because of the signalling fault, which began affecting services before 4pm.
The travel misery affected thousands of passengers on the eve of the Commonwealth Games.
Scores of visitors have already began flocking to the city for the biggest sporting event ever held in Scotland.
Rail operator ScotRail urged passengers not to travel Glasgow Central today.
On their Twitter account, ScotRail staff said: "Please don't try to travel from Glasgow Central until further notice due to Network Rail signal problem.
"Services to and from Glasgow Central may be cancelled, delayed or revised at short notice."