A potential Red Line-Blue Line connector is back in the spotlight By Adam Vaccaro Globe Staff,Updated May 9, 2021, 6:56 p.m. Email to a Friend A long-proposed connector would extend the Blue Line from Bowdoin station to the Charles/MGH Red Line Station.David L. Ryan/Globe Staff Every now and then, it seems, one of the long-debated MBTA expansion projects resurfaces and captures the publicâs attention for a brief period before quickly receding into the annals of ideas gone by. That has been the lifecycle of the Red-Blue connector â the on-again, off-again idea to extend the Blue Line a short distance down Cambridge Street to the Charles/MGH Red Line Station, finally linking the only two subway lines that donât currently connect.