The project hit delays two years ago because of a dispute between Amtrak, which owns the rail bed, and the state Department of Transportation, which is adding a second track, modernizing signals, rebuilding bridges and constructing new stations. The DOT and Malloy complained that Amtrak was mismanaging construction and incurring overruns. After Connecticut put in extra money this winter, though, crews have been working rapidly to meet the new target for starting service: January 2018.