East Lyme - A peculiarly shaped structure with one end resembling a heel was lifted slowly into the air Tuesday.

Known as the "heel girder," the steel bridge component was moved from the barge that had delivered it here to the same barge that held the crane. To control it, several workers manned lines attached to the corners of the girder.

The pointed, lighter end touched the barge first. Then the crane gently lowered the heavier end, which ultimately will connect to the rest of the structure that will open the bridge.

The challenge was to keep the crane barge level, even with the heavy girder on one side. It's not allowed to tilt more than a degree. Water could be shifted between ballast tanks or concrete blocks could be repositioned if the barge shifted.

After unloading smaller beams and parts Monday, the contractor, Cianbro/Middlesex Joint Venture Team, tackled the massive bridge parts Tuesday.

Amtrak is building a two-track, electrified, railroad bascule bridge across the Niantic River between East Lyme and Waterford, 58 feet south of the current Niantic River Bridge. A barge carrying the major steel components for the mechanism that will open and close the new bridge, called the lift span, arrived at the Niantic project site over the weekend from the steel fabricator, G&G Steel in Alabama.

The heel girder was one of two onboard the delivery barge. Their function is to hold the solid lead blocks that act as a counterweight when the bridge opens, as well as the gear that will open and close the bridge. Bearings on which the bridge will pivot protrude from their sides.

In the next step Tuesday, a tug boat maneuvered the delivery barge about, positioning it so the second heel girder was close to the crane.

By mid-afternoon, both heel girders were on the crane barge, and the crews had turned their attention to the last of the bridge components - two long, rectangular steel beams - to be unloaded.

Peter Finch, project manager for Amtrak, said the unloading should be done today as planned so the barge can be sent back on time. The $125 million bridge, funded with federal stimulus money from the American Recovery and Reinvestment Act and Amtrak's capital budget, is expected to be complete in May 2013.

As early as next week, the two heel girders will be placed on towers that have been built on a pier, Finch said. The rest of the parts will be assembled on a floating barge over the next two months.

Once complete, the lift span will be raised using hydraulic jacks, floated into place and fitted into the heel girders.

This month, the Amtrak crews also will weld 80-foot sections of rail together into quarter-mile sections of track. The east approach to the bridge will be put into place in early April. The piers and abutments for the shorter approach on the west side are already there.

The old bridge will be demolished next winter.

j.mcdermott@theday.com