LIRR Main Line Third Track Expansion: Project Profile

The Long Island Rail Road (LIRR) Main Line Third Track Expansion is a transformative infrastructure project that has fundamentally increased capacity and reliability on one of the busiest commuter rail corridors in North America. This initiative involved adding a 9.8-mile third track along the LIRR’s Main Line, eliminating critical bottlenecks and enabling a significant increase in service frequency. The project represents a major modernization effort, integrating advanced engineering with extensive community and environmental considerations to reshape regional transit.

Technical Specifications

The core of the project was the construction of a 9.8-mile third track within the existing LIRR right-of-way, a complex undertaking that required meticulous staging to maintain ongoing rail operations. This expansion directly addresses the capacity limitations of the former two-track system, which created a significant bottleneck for approximately 40% of LIRR’s daily ridership. Upgrades to signaling and power systems were implemented along the corridor to support increased service frequency and bidirectional express service, enhancing operational flexibility.

A major component involved significant civil infrastructure upgrades to improve safety and reduce community impact. Seven street-level grade crossings were eliminated and replaced with underpasses, a critical safety measure that mitigates vehicle-train collisions and alleviates local road congestion. Furthermore, seven bridges along the route were raised or completely replaced, such as the 103-year-old Post Avenue Bridge in Westbury, to provide greater vertical clearance for freight and improve structural integrity. Station modernization was also key, with five stations—New Hyde Park, Merillon Avenue, Mineola, Carle Place, and Westbury—receiving comprehensive upgrades, including ADA-compliant accessibility, new platforms, and improved passenger amenities.

Key Takeaways

• Alleviated Core Bottleneck & Increased Capacity: The addition of the third track resolves a long-standing chokepoint on the LIRR Main Line, increasing peak-hour capacity by over 80% and drastically improving on-time performance and service reliability.
• Enabled Full Potential of East Side Access: This expansion was a critical prerequisite for the success of East Side Access (now Grand Central Madison), allowing the LIRR to run significantly more trains to both Penn Station and Grand Central Terminal without creating system-wide delays.
• Enhanced Safety and Community Livability: The systematic elimination of seven grade crossings has permanently removed points of conflict between trains and road traffic, dramatically improving safety for motorists and pedestrians while reducing noise and traffic backups in local communities.

Frequently Asked Questions (FAQ)

When did the LIRR Third Track project open?

The LIRR Third Track expansion project became fully operational in October 2022. The completion marked the culmination of years of construction and allows for significantly increased and more reliable train service along the Main Line corridor.

Who built the LIRR Third Track expansion?

The project was managed by New York’s Metropolitan Transportation Authority (MTA). The construction was executed using a design-build contract awarded to a consortium, with key contractors including Halmar International. Comprehensive environmental review and engineering support were provided by firms such as Gannett Fleming and AECOM.