There's currently no Silver Line portal near South Station, just an underground loop. They'd have to add a portal.
Understood. My question is whether a portal can be added without having to demolish buildings.
There are only so many cars a bus unit can carry behind it, so on one level it's a capacity issue. The Green Line (with its ridiculous two car combos) isn't the best poster child for the possibilities of LRT.
There are also arguments about the perceptions LRT generates - that it represents a more serious and long term investment due to the relative permanence of rail infrastructure, and thus attracts more investors / residents whose businesses won't be affected by reroutings.
The Silver Line from SS to the airport and BCEC is every bit as comfortable as the Green Line.
You can't compare the speed or comfort of the bus to an underground trolley.
That's why I think the relevant comparison is the Green Line.
A ride on the Green Line is much, much smoother than the crumbling Silver Line tunnel. Opened very late 2004 (essentially 2005), started turning to gravel by 2009, still un-repaired in 2010. No one at the MBTA will acknowledge it.
Meanwhile the GL is running on rails that were laid down decades ago.
I admittedly haven't ridden the SL in two couple years. I'm surprised (disappointed) to hear that the tunnel is in a sorry state.