(LOL look at page 8&37 for an artists impression of the plan complete with what seems to be steps in the middle of the bike path!)
I think that's an optical illusion caused by the striped ramps at the platform ends.
Getting the striped platform/bike lane concept to work will require an incredible amount of education of both pedestrians and cyclists.
Pedestrians will have to learn to stay on the footpath proper until a tram arrives at which point the bike lane will become a boarding platform.
Cyclists will have to learn to wait until trams have finished picking up or setting down passengers at which point the boarding platform reverts to a bicycle lane.
I can work with that but a large section of the both groups will have trouble grasping the concept.
I reckon you'll need police, council or public transport officers handing out fines on every Swanston St stop for three months to get anything like compliance.