Imagine taking a train — a one-seat ride — all the way from Grand Central Terminal to the sandy shores of Mystic. Or connecting there for a quick run up to the Indian casinos. Such a thing should be possible and may yet happen — if Shore Line East gets its act together. Shore Line East is the state-owned commuter line from New Haven to Old Saybrook opened in 1990 in anticipation of heavy traffic delays on I-95 during reconstruction of the Q Bridge. Initially it was only rush-hour service, west to New Haven in the morning and back east in the evening.