A new rail bridge set to soar above the Western Ring Road as part of a $10bn Airport Link will be four storeys high and designed to minimise closures of the busy freeway.

The massive structure, which would be 80m long, is part of a package of works released to market that should enable shovels to be in the ground within two years.

Project teams have been forging ahead with soil and fauna testing over the past few months, with 250 site investigations already completed.

Construction of the Melbourne Airport Rail Link has been split into several packages, with the most recent to hit the market the “viaduct” or sky rail section of the project, as well as the airport station.

As revealed earlier this year, an elevated station at Tullamarine is still an option being considered by project designers and airport owners. Locations for a series of substations to powertrains on the line have also been revealed, including near Munro Ave in Sunshine North, Keilor Park Drive in Keilor East, and in Keilor Park near Terror St and the M80.

Plans showing the route of the Melbourne Airport Rail Link, which will be built via several packages of work.

The city-shaping project, which is funded by state and federal governments, will open in 2029 and give passengers at 30 city and suburban stations direct access without changing trains.

The trip is likely to take 30 minutes from the heart of the CBD.

Transport Infrastructure Minister Jacinta Allan said the rail link would slash travel times and be “supporting local jobs along the way”.

“We’ve divided up these packages to create more opportunities for local contractors as we get this vital project underway,” she said.

“While construction on the project is targeted to start next year, works on the station and new rail bridge are targeted to start in 2023.”

As well as ensuring there are minimal closures of the M80, the rail bridge will help protect the M80 Trail — a 43km shared user path popular with cyclists.

Rail Projects Victoria project director Ben Ryan said consultation with airport owners was continuing about the best design and option for a Tullamarine terminal station.

“The new station at Melbourne Airport and the new rail bridge over the busy M80 freeway will be two key jewels in Melbourne Airport Rail’s crown, so progressing these packages of work is an important milestone as we continue to work with the airport owners to land on the best outcome,” he said.