Two steel rail bridges in US replaced in a weekend

In a smoothly executed, rapid transformation operation, two rail bridges in the East/West Stonington Harbor, Stonington, Conn., USA, that were over 100 years old were replaced with new steel spans to increase the clearance for boats passing beneath. The entire replacement was carried out within a single weekend resulting in minimal disruption to both rail and water traffic that travel on and below the bridges.

The original bridge clearance was not great enough to facilitate the free flow of boats to and from nearby marinas, and this necessitated the change. The railway consists of two ballasted tracks on the same alignment located on a causeway, with low clearance over harbor channels, approximately 800 ft apart.

The operation was carried out by bridge engineering firm Modjeski and Masters, who used accelerated bridge construction techniques to complete the bridge replacements in record time.

Experts from the firm created the designs for the new bridge, adding an extra two feet above the water level for greater clearance, and also laid the groundwork for a quick transition. Working in close coordination with Amtrak and Cianbro, the teams from the specialist firm erected 1,200 tonnes of structural steel for the new bridge superstructures on roll-in falsework adjacent to the existing bridges.

The urgency behind the operation was on account of the fact that more than 200 trains travel over the bridges every week along the Northeast Corridor i.e. nearly half of Amtrak’s nationwide ridership.