The Tomlinson Vertical Lift Bridge carries four lanes of traffic across New Haven Harbor and a single-track freight line owned by the Providence & Worcester Railroad that connects the waterfront with the Northeast Corridor line of Metro North and CSX.

[5] The third bridge on-site was a trunioned double-leaf bascule drawbridge with its counterweights in a closed pit underneath, built between 1921 and 1924.

[4] The mechanism raises the lift span 62 feet (19 m) with 3,000,000-pound (1,400,000 kg) counterweights on each of the two 150-foot (46 m) towers on either end.

The project was part of the New Haven Harbor Crossing Improvement Program Securing the bridge's lift piers initially proved difficult because rock elevation and slope differed along the route.

To secure the piers, teeth were welded to the tip of 20-in-diameter pile shells that were then drilled into the bedrock.