Melbourne commuters have experienced major disruptions caused by a fire near a rail line.

Train services at Southern Cross Station, one of Melbourne’s busiest, were brought to a halt in both directions when a fire broke out beneath the Dudley St rail bridge in West Melbourne.

Emergency services were called to a burning 30 by 10-metre Metrol storage building under the bridge on Roslyn St about 3pm on Wednesday.

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“Firefighters arrived on scene within six minutes to find a large fire underneath a railway bridge,” a Fire Rescue Victoria (FRV) spokesperson said.

Six lines were affected, including Craigieburn, Frankston, Sunbury, Upfield, Werribee, and Williamstown.

The fire broke out underneath a railway bridge. Credit: Facebook

Flames and smoke can be seen rising from beneath the bridge in photos taken at the scene.

FRV told 7NEWS.com.au the blaze was brought under control by 3.40pm.

Three firefighters in breathing apparatus located the seat of the blaze and contained it to the underpass, the FRV spokesperson said.

There was evidence the structure had been occupied by squatters, but no one was inside at the time of the fire, the spokesperson added.

No injuries have been reported.

The cause of the fire remains unknown and is under investigation.

Smoke can be seen rising above train lines. Credit: 7NEWS