For the safety of passengers when getting on and off the light rail cars, and for wheelchair access required under the Americans with Disabilities Act, the track pulls over to the curb. To avoid crossing the track and risking a diversion-type fall, a bicyclist must keep left. No such luck if entering from a street to the right. Now imagine riding or driving on this street when there is a train. Unlike a bus, the train is forced to merge right and left at fixed locations.
And if one streetcar breaks down, is stopped by a crash ahead or other congestion, others can't merge to the next lane or reroute to get past it. Neither can the route be changed to reflect changing demand. Why choose a streetcar line over buses? Beats me!