United Illuminating has completed a major milestone in an ongoing, decade-long project to remove a critical section of its transmission grid from century-old structures owned by Metro-North Railroad.

At the end of last month, nearly six months ahead of schedule, UI energized a 2-mile span of 115-kilovolt transmission lines from the western bank of the Housatonic River to UI’s Baird Substation in Stratford.

The marked the successful completion of Phase 3 of the UI Railroad Transmission Line Upgrade Project, the company’s five-phase, long-term effort to separate its high-voltage transmission lines from Metro-North equipment along a 25-mile stretch of the railroad corridor, running from New Haven to Fairfield.

The UI transmission lines were originally strung atop the same structures that carry the railroad’s overhead catenary lines, which supply power to Metro-North trains. The project requires relocating the transmission lines to new independent support structures along the railroad corridor. It includes installation of approximately 500 new foundation-supported galvanized transmission poles, upgrading of conductor size and installing sectionalizing switches at nearby substations.

Customers will enjoy the benefits in the form of improved reliability, capacity and storm-resiliency of the regional transmission grid with improved access to the lines.

UI and its contractors logged more than 80,000 construction hours and overcame significant challenges in order to complete Phase 3 ahead of the original August 2021 deadline. The work took place on the nation’s second-busiest rail corridor, requiring tight coordination with the railroad — which is simultaneously undertaking a major infrastructure upgrade of its own. Meanwhile, UI workers and contractors had to contend with severe weather, including Tropical Storm Isaias last August, and the new health and safety protocols introduced as the COVID-19 pandemic took hold.

None of these challenges were able to derail the project. In fact, the project team was able to exploit the reduction in rail traffic caused by COVID to accelerate work on the project.

Work began in December of 2010 to address the FAC-008 NERC Compliance requirements and is scheduled to continue until 2028. The final two phases of the project are expected to launch in 2023 and 2024, respectively.