The government is avoiding the controversial sky rail option and will instead lower the train line into a trench to improve traffic at the three crossings,which have a total of 38,000 vehicles driving through them every day.
The building work will start in the middle of next year and the stations could each be closed for about four months,while the station car parks at each site could be closed for about 18 months.
The government has assured locals that the heritage-protected train stations would be incorporated into the new design.
A new"garden bridge"will be built over the sunken railway lines at Mentone station to connect the two platforms of the existing station,while the new Cheltenham station will have a plaza connecting Cheltenham Park with the local shops.
A third platform at Cheltenham station will be connected to Frankston-bound tracks,so that trains can terminate or originate without getting in the way of Frankston services.
More than three kilometres of walking and cycling tracks will also be created.