All of Melbourne's train services are back online, after workers accidentally cut through cables in the CBD this morning.
Five metropolitan lines were down for about six hours and all regional train services were also affected by the signal outage.
Buses replaced trains on the Craigeburn, Sunbury, Werribee and Williamstown lines, and other services had to be redirected to Flinders Street to avoid the city loop.
V/Line said its services were also prevented from leaving Southern Cross station.
The problem was resolved about 4:00pm AEDT.