The Metropolitan Transportation Authority (MTA) in New York City recently marked a key milestone in its Park Avenue Viaduct repair and replacement project for the agency's Metro-North commuter train service.

Earlier in October, New York Gov. Kathy Hochul and MTA officials announced at a press conference that work had finished on the last of the project's Phase 1 bridge installations, which began in 2023.

The $590 million first phase ($500 million of which was funded by the federal government) is slated for total completion next year and, along with the ongoing second phase, is designed to reconstruct or replace portions of the 132-year-old East Harlem viaduct that carries Metro-North riders.

According to a news release from Hochul's office, the completion of this part of the overall viaduct upgrade was due to "strong project management and an innovative construction approach." In addition, the entire project is currently $93 million under budget and 51 months ahead of schedule.

"For the last 100 years, [the Park Avenue Viaduct has] been falling apart," said Janno Lieber, MTA's chair and CEO. "This is a story about what we're dealing with in the MTA capital program. In this viaduct, there are structural elements that were put there, maybe by Cornelius Vanderbilt himself back in the 1890s."

The viaduct — a bridge with multiple spans — is considered the backbone of the Metro-North Railroad. The elevated structure in East Harlem supports four Metro-North tracks and carries about 750 trains on a typical weekday, reported amNY.com, an online news source serving all five New York city boroughs.

The train service runs for nearly 2 mi. from the entrance of the Park Avenue tunnel at 97th Street to the Harlem River.

Without it, Metro-North would not be able to provide service to Manhattan for riders from the Bronx, Westchester, Putnam and Dutchess counties, nor the state of Connecticut. Since it was built at the end of the 19th century, significant portions of the viaduct require comprehensive rebuilding from time to time due to decades of heavy use.

Hochul, whose office runs the MTA, said riders will benefit from the project with safer and more dependable service.

"The Park Avenue Viaduct is a lifeline for hundreds of thousands of Metro-North riders and now, riders will benefit from a more reliable ride for decades to come," she said in a news release. "Completing work on an elevated structure that dates back to the Gilded Age, [both] ahead of schedule and under budget, shows what's possible when we modernize our infrastructure and put riders first."

Halmar International, located in Nanuet, N.Y., was the design-build contractor for Phase 1 of the viaduct project.

Unique Gantry System Did Much of the Heavy Lifting

The latest work to upgrade the Park Avenue Viaduct is a key example of the MTA's new approach to construction using better, faster and less expensive methods, according to Hochul's office.

Phase 1 kicked off in October 2023 to replace the full substructure and superstructure from East 115th Street to East 123rd Street along Park Avenue as well as the installation of new track, power, communications and signal systems across the new sections.

Using an innovative and custom-built gantry system erected over the viaduct that spanned Park Avenue, Halmar was able to replace whole sections of the existing concrete and steel bridge deck with new prefabricated bridge units. The method allowed workers to lift out deteriorated steel and concrete deck segments and install new sections without shutting down Metro-North service on the other side of the structure.

That approach emerged during the design-build procurement phase between the MTA and Halmar. By allowing the contractor to propose its construction techniques, the project eliminated the need for longer-term shutdowns and accelerated multiple phases simultaneously. As a result, Phase 2 of the viaduct renovations, which stretches from East 127th Street to East 132nd Street, was able to start in May 2024.

As part of its work on Phase 1, Halmar's crews replaced 8,240 ft. of aging track across 128 new bridge sections as well as add 12,800 ft. of new aluminum third rail (which provides electricity to commuter trains); 6,500 ft. of signal cables, 25,000 ft. of new running rail and more than 40,000 ft. of new communication cables over 19 weekends since June 2024.

Jamie Torres-Springer, MTA's president construction and development, said workers also added safety features that were not included during the viaduct's initial construction. They included walkways for maintenance workers and an increase in vertical clearance at intersections over roadways to reduce bridge strikes from higher trucks that try to pass under the viaduct.

Other project improvements include a reduction in noise and vibration levels and a permanent art installation at 116th Street.

"This is one of the most complex and high-stakes state-of-good-repair projects currently under way," Torres-Springer said.

Now halfway through its construction, the complex Park Avenue Viaduct project is expected to be ready for the public in 2027, according to the MTA.