Arriving within five minutes firefighters found a 5m x 15m switching room on fire and quickly worked to cordon off the area and suppress the blaze.
The scene was brought under control at 4:56pm. There are no reported injuries.
Trains will not stop at Broadmeadows until further notice and replacement buses will operate between Glenroy, Broadmeadows and Coolaroo Railway Stations.
Five Pumpers, a Rescue Unit and a Teleboom were assisted by three specialist and support vehicles.
Victoria Police is assisting with traffic control.
Reviewed 03 June 2021