A UGL Rail employee was knocked unconscious at the Gregory Street site yesterday.
The 51-year-old, who also received facial fractures, was working on a train axle whern a piece of equipment struck him in the face around 12.30pm.
Police attended the scene, with the man taken to St John of God hospital in a stable condition.
Worksafe were notified and will investigate the incident.
A spokesperson for UGL Rail did not wish to comment.