[Life on easy street]

I was incorrect there are over 20 trains per hour at peek times to the city from south yarra
Only 8 trains per hour from Toorak.

Map of train & tram lines
http://www.railpage.org.au/railmaps/melbourn.htm

The quickest route from the South Yarra is
The train to Melbourne Central or Flagstaff , then tram to The Royal Melbourne hospital

Frankston Line
South Yarra 08:00
Melbourne Central 08:08
Flagstaff 08:10

About 6 trams per hour 10 min to The Royal Melbourne hospital.