Peak hour trains have been stopped while firefighters battle up to eight grass fires north of Melbourne.

Twelve MFB trucks and CFA back-up are at the small blazes at Glenroy, all of them near the Jana train station.

Tom Elliott has been told it is suspected the fire was caused by a goods train travelling along the Broadmeadows line.

As a result, buses are replaces trains between Essendon and Craigieburn.