Putting a third track between Wentworth Park and Central is a good idea in theory, but not in practice.
Extending the platforms and buying more tram cars is far more feasible and would cost a fraction of a third track.
In an ideal world, I think a better plan would be to create a new alignment branching at Rozelle Bay and heading towards the city via the new Bays Precinct, over the Glebe Island Bridge, passing through Pyrmont along Miller and Union Streets, then over the Pyrmont Bridge. Inbound track to turn left onto Sussex then right onto King, proceeding all the way up to Queens Square. Outbound track returns to Pyrmont Bridge via St James Rd and Market Street to complete the loop.
Would likely divert a significant chunk of passengers away from the existing alignment and provide a faster connection with the city centre. But I'll stop dreaming and also say that this thread has gone way off-topic.Back to physical distancing:
Outbound bus passenger numbers in Sydney CBD for the PM peak have been increasing steadily over the last 3 weeks. I would estimate that around 15-25% of buses are now going over their new soft "limit" but this is almost always the result of uneven loading (for example, one bus will leave with 20 people, and another will follow right behind with less than 5 people).
This varies depending on the corridor but also the individual routes within each corridor. On some days the B-Line buses from Wynyard have been at or over 25 people 80+% of the time, whilst the other Region 8 (Military Road / Northern Beaches) express commuter buses leave practically empty. So right now there is probably enough bus capacity to enforce the new limits, but this may change over the coming weeks as more people return to work.