Problems with a level crossing between Gartcosh and Cumbernauld are causing delays and cancellations between the transport hub, Cumbernauld and Falkirk Grahamston.
Services are starting to return to normal but disruption is expected until 7.30pm this evening.
Scotrail have provided replacement bus services to accommodate passengers.
A Scotrail spokesman said: "Due to a problem at a level crossing between Gartcosh and Cumbernauld, services between Glasgow Queen Street and Falkirk Grahamston are currently disrupted.
"Alternative routes are available between Glasgow Queen Street and Croy, with tickets between Glasgow Queen Street and Cumbernauld also being accepted on this route."
The crossing fault is also affecting services between Motherwell and Cumbernauld, and a replacement bus service has been provided for passengers.