One of the unsolved problems is getting from the Back Bay hotels to the Convention Center. You have to take the Green Line to Park Street, then the Red Line to South Station, and then the Silver Line to World Trade Center. Very unlikely that visitors will want to do this and, as a result, conventions use a fleet of big slow chartered interstate busses. Silver Line phase III would reduce this from 2 changes to one, but that's never going to happen. Suggestion: establish a trackless trolley line running from the vicinity of the Sheraton Boston, thence along Stuart Street eastbound (St James Avenue westbound), Kneeland Street, and into the Silver line tunnel where the present loop is, terminating at Silver Line Way.