The Clamdigger was a daily passenger train which ran along the Northeast Corridor during the 1970s. The train had two iterations: from 1898 to 1972 it was a local commuter service under the New Haven Railroad, Penn Central, and Amtrak between New London and New Haven, while from 1976 to 1978 it was a long-distance commuter service operated by Amtrak from Providence to New Haven. In 1978, it was canceled and replaced with the Beacon Hill.
The Shore Line East service, run by the Connecticut Department of Transportation, currently runs from New London to New Haven, serving many of the same stops as the two incarnations of the Clamdigger.