The $395 million project will support some 1000 jobs during peak construction, including more than 30 apprentices and trainees over the life of the project.
The second track to Rosanna will remove the notorious section of single track between Heidelberg and Rosanna that causes delays and stops new services being added to the busy line.
The project will also remove two dangerous and congested level crossings at Grange Road in Alphington and Lower Plenty Road in Rosanna and build a new Rosanna Station.
These level crossings are among Melbourne's worst, with boom-gates at both sites down for around 40 minutes in the morning peak, causing delay, distress and frustration for thousands of motorists every day.
Removing the crossings will reduce congestion, improve safety and with the duplication of the line between Heidelberg and Rosanna, create space for more trains, more often right along the Hurstbridge line.
Over the coming weeks, construction crews will establish work sites, remove vegetation and relocate underground services.
The Hurstbridge line upgrade will be complete by 2019.