The bridge carries four tracks over the river at the point where it empties into the Hudson River. Only the westernmost track, Track 4, is being replaced. All work will be performed from barges in the Hudson River. No work in the water is needed, as the two concrete abutments and the three piers are in good shape, having been rehabilitated in the 1990s.
The track is carried by four spans, each 100 feet long. Beginning in mid-June, when the track comes out of service for trains, each span will be demolished, hoisted onto a barge, removed and replaced, one at a time, on new concrete pedestals atop the existing piers.
There will be no work in the river, no dredging or filling. All staging, trailers etc. will be in the rail yard.
In cooperation with the New York State Department of Environmental Conservation, the railroad will be using several environmentally-protective measures and the railroad will follow United States Coast Guard procedures for properly securing the barges.
New spans, each weighing about 220 tons, will be floated to the site at high tide to minimize disturbance to the river bottom, then hoisted into place by crane.
A $4.27-million contract was awarded in December to Halmar International of Nanuet, N.Y. It includes an incentive clause for early completion before June 26, 2014.
The work will not affect train service at the Croton-Harmon Station, just a quarter of a mile north of the bridge. To prepare for the Track 4 outage, the railroad reconfigured the track layout north of the bridge so that trains could still reach the station platform.