Day-to-day struggles weigh down the T's ambitious improvements

MBTA CEO and General Manager Phil Eng has promised to rid the subway system of all slow zones by the end of this year. He's also endorsed big plans for the future of transit in the region.

But sometimes— like Saturday, when a derailed train snarled Green Line service for hours— it seems like the T is standing in its own way on the path to a brighter future.

Boston Globe transportation reporter Taylor Dolven, State Rep. Russell Holmes, and Brain Kane of the MBTA Advisory Board join Radio Boston to dissect another wild week at the T.