McLaren Engineering completes design work on new LIRR bridge

Westbury, N.Y. — McLaren Engineering Group completed its design work on a new $9.7 million railroad bridge used by the main line of the Long Island Rail Road (LIRR), spanning Post Avenue in Westbury, N.Y. The new bridge replaces a 103-year-old structure and is 13 feet wider and 2 feet higher than the original.

“Built in 1914, the 63-foot single span bridge carried two tracks supported by steel girders. It was desperately in need of an upgrade,” says Shea Thorvaldsen, director of infrastructure, McLaren Engineering Group. “Research showed us the low height of the old bridge caused between five and nine trucks traveling below the bridge to hit it per year, leading to extensive train delays. Our design made the bridge wider and higher to avert delays and prevent trucks from striking it from below.”

McLaren, in association with Halmar International, began work on the design of the new Post Avenue Bridge in January 2017. The goal was to provide an economical design with the least amount of impact to the community. McLaren’s design replaced the existing tracks, increased vertical clearance, strengthened existing abutments, raised existing station platforms and replaced the existing stairs from the parking lot to the platform.

To minimize traffic and rail disruptions, McLaren assembled the bridge superstructure on temporary shoring towers in the parking lot of the adjacent Westbury train station. Once assembled, the team of engineers used a 48-hour weekend track outage to remove the existing bridge superstructure and roll the new superstructure into position using self-propelled modular transporters. The bridge superstructure was literally “driven” down the street and placed into position.

“We are proud to have completed this project ahead of schedule and within budget for the local government and LIRR,” says Malcolm G. McLaren, president and CEO, McLaren Engineering Group. “Our team uses applied ingenuity to provide innovative engineering solutions that minimize disruptions and increase safety for transportation infrastructure projects across the NY metro.”

The new bridge was designed 13 feet wider to allow for the addition of a third track that will increase the flow of train traffic on the Long Island Rail Road mainline. It is part of New York State’s initiative to upgrade the LIRR to keep up with increased rider demand and update century-old infrastructure.

“After 70 years of stagnation, New York is regaining its building spirit and transforming the LIRR into the 21st century commuter rail that Long Island deserves,” says Governor Andrew Cuomo of New York. “By rebuilding the Post Avenue Bridge and paving the way for the historic Third Track project, we are showing that it’s possible to upgrade the LIRR on time, on budget, and with community input at every step of the way. While others talk about infrastructure, New York is getting it done.”

Construction is expected to be complete on the site in early spring 2018 once final adjustments are made on the platforms and stairs, as well as painting and sealing work.