At some point next year Metro North will extend one round-trip from Poughkeepsie to Rensselaer, encroaching into this Amtrak-exclusive territory for the first time.
I believe this would be the longest (mileage) one-seat commuter-rail ride in the country, at 141 miles (longer than longest direct LIRR trains such as the Cannonball from New York’s Pennsylvania Station to Montauk, which is about 118 miles in length). The Cannonball takes 2h49m to get to Montauk. Amtrak takes about 2h30m to 2h40m to get from Pennsylvania Station to Rensselaer. Presumably the Grand Central-Rensselaer train will take longer than that if it makes additional stops that Amtrak would not make (such as Harlem, Beacon and New Hamburg at the very least). Currently the longest (in terms of time traveled) one-seat commuter rail ride in the country is believed to be LIRR train #18, which leaves Hunterspoint Avenue at 4:30pm and arrives in Montauk at 7:41pm, for a total time traveled of 3h11m.
https://www.mta.info/press-release/icymi-governor-hochul-restores-service-and-announces-further-improvements-rail
To provide mitigation for rail commuters affected by the suspension of Amtrak service during the rehabilitation of East River Tunnel, Governor Hochul challenged the MTA and Metro-North Railroad to develop a plan to run Hudson Line service beyond Poughkeepsie to connect Grand Central Terminal with Albany-Rensselaer Station. Metro-North is now advancing a plan to commence this service in early spring of 2026, with non-passenger test trains set to run later this year.
The planned schedule will fill in gaps left by Amtrak service that was suspended earlier this year, with the Grand Central to Albany train departing at mid-morning and the Albany-Rensselaer to Grand Central train departing in the afternoon and arriving at Grand Central in time for evening events in New York City. This service would be the first time Metro-North has run between New York City and New York’s Capital Region. Metro-North’s predecessor on the Hudson Line, the New York Central Railroad, previously ran service between Grand Central and Albany until 1967, including on the iconic 20th Century Limited train to Chicago.
Also, beginning in December one round trip between Rensselaer and Pennsylvania Station will be restored, and the Lake Shore Limited section between Boston and Rensselaer will also be restored (it was “bustituted” after a sinkhole damaged the tracks earlier this year).
Following the cancellation or consolidation of three weekday round trips between Albany and New York Penn Station earlier this year to accommodate Amtrak repairs to the East River Tunnels in New York City, Governor Hochul sought the restoration of as much rail service as possible along the corridor. In support of these efforts, Amtrak will be restoring one round trip between Albany and Penn Station on December 1. Amtrak has also committed to a first-of-its-kind price cap on trips between Albany and New York City, with coach seats capped at $99.
Amtrak will also restore direct rail service between Albany-Rensselaer and Boston on the Lake Shore Limited on December 1, which is currently running with a temporary bus service. This restoration will reconnect rail service between Albany and Massachusetts for the over 80,000 Lake Shore Limited riders who use the station.