The stretch, which lies south of the Croton-Harmon stop, is the only one of four tracks along the route that doesn’t have a third rail, according to the solicitation document. A single, diesel-only track where all the others are electric is an unusual arrangement, says Blair Lorenzo, the executive director of the Effective Transit Alliance, an organization that advocates for improved transit in the New York region.

The construction site lies within what the MTA calls its “third-rail territory,” or 102 miles of Metro-North that have electric capacity and extend up the Hudson, New Haven and Harlem lines. In September last year, the department announced that new Siemens Mobility Charger locomotives were starting to operate along the Husdon line specifically. While older models on the tracks only run electric within the tunnels of Grand Central Terminal, the Charger locomotives are built for long-distance, high-speed electric travel, Lorenzo says. Completing this final bit of electrification on the Hudson line would let the new models operate diesel-free all the way to Croton-Harmon.

“At ETA, we believe that electrification of greater New York's commuter rail network should be a high priority, especially on high-ridership lines like the Hudson Line,” Lorenzo says. 

The organization advocates for catenary instead of third-rail conversions, however, because the former is cheaper, safer to repair, and allows higher top speeds.

The MTA declined to comment on this particular request for proposals or what it means for electric commuter train deployment. The agency 2025-2029 capital plan notes that the MTA plans to keep buying new electric-diesel locomotives for the Metro-North and replace third-rail that is in poor condition throughout the train lines. 

Besides completing the electric train capabilities in the area, the contractor will also replace four undergrade bridges and complete four rock slope stabilization projects along the Hudson line.