At the inception of
Amtrak on May 1, 1971, the
Delaware and Hudson Railway (D&H) operated two trains between
Albany, New York and Montreal: the
Montreal Limited (overnight) and the
Laurentian (day). Both trains were discontinued, and for three years the D&H main line saw no service. Amtrak service to Montreal began in 1972 with the
Montrealer, which ran through
Vermont rather than New York. The
Adirondack began running on August 6, 1974 (with a ceremonial train the previous day) from
Grand Central Terminal in New York to Albany, then over the D&H's line to
Windsor Station in Montreal. From the outset the train operated with financial support from the state of New York. The train initially operated as a section of the New York–Buffalo
Empire State Express. Initially, the
Adirondack used the same routing as its D&H predecessors, running over the former
Rensselaer and Saratoga Railroad via
Watervliet and
Mechanicville, New York, and over the
Schenectady–Mechanicville freight bypass to Saratoga. With the April 30, 1978, timetable change, the
Adirondack dropped both stops but continued to use the route. The train was re-routed via
Schenectady on October 29, 1978, but did not start stopping there until January 29, 1979. Both termini have shifted since service began. In Montreal, the
Adirondack moved to the
Canadian National Railway's
Central Station on January 12, 1986. In New York City, the opening of the
Empire Connection on April 8, 1991, allowed the
Adirondack to serve
Penn Station instead of Grand Central.
21st century As part of an effort to improve on-time performance along the Empire Corridor, Amtrak reached an agreement with CSX to lease the CSX Hudson Subdivision between
Poughkeepsie and Schenectady. Starting in 2012, Amtrak effectively took operational control of the Hudson Subdivision, handling all maintenance and capital responsibilities. Even with this move, Amtrak still operates less than half of the trackage along the
Adirondack route. In 2012,
U.S. Customs and Border Protection began planning a
preclearance facility at
Montreal Central Station, which would allow departing passengers to be prescreened in Montreal, where northbound passengers would be processed by the
Canada Border Services Agency upon arrival, rather than at the border itself. Presently, the
Adirondack must stop at
Lacolle, Quebec northbound and
Rouses Point, New York southbound for immigration procedures that can take up to two hours. By early 2017, the
United States Congress had passed its necessary enabling legislation. The corresponding Canadian legislation was given
royal assent in late 2017 and came into force in 2019. All trains using the
Empire Connection, excluding the
Lake Shore Limited, operated into Grand Central Terminal from May 26 to September 4, 2018, to allow work on the Empire Tunnel, the
Spuyten Duyvil movable bridge, and Penn Station. For most of the summer of 2019, the northbound
Adirondack ran combined with the northbound
Maple Leaf due to infrastructure work at Penn Station, splitting in Albany. The two trains ran separately on weekends during July and August.
COVID-19 pandemic and track issues In March 2020, the
Adirondack was truncated to Albany–Rensselaer after all non-essential travel across the
Canada–United States border was banned in response to the
COVID-19 pandemic. In July 2021, that truncated service was replaced by the resumption of
Ethan Allen Express service, which overlaps the
Adirondack between New York City and . Weekday service from
New York City to Albany resumed on December 5, 2022. Full service resumption to
Montreal took place on April 3, 2023; the Port Kent stop remained closed, as service on the Port Kent-Burlington Ferry remained suspended indefinitely. The Canadian National Railway (CN) owns the
Rouses Point Subdivision, a section of track that runs from
Rouses Point, New York, to the vicinity of Montreal. During the COVID-19 suspension track conditions "deteriorat[ed]", forcing Amtrak to lengthen an already long running time between Rouses Point and Montreal. Citing a concern over
heat kinks, CN imposed a speed restriction when temperatures exceeded , leading to one trip over in mid-June taking four hours. On June 26, Amtrak suspended service "until further notice" north of Albany over the track conditions. Amtrak criticized "inconsistent application of CN's historical heat order policy"; CN claimed that Amtrak had failed to pay for maintenance to the track, which Amtrak disputed.
Adirondack service was extended to on July 24, 2023, to serve the
Saratoga Race Course meet. Trains were turned using a
Canadian Pacific Kansas City (CPKC)
wye near Saratoga Springs. Montreal service resumed on September 11. The
Adirondack was again suspended north of Saratoga Springs on May 20, 2024, due to unspecified track work. On May 17, 2024, Amtrak and CN announced an agreement under which Amtrak would pay CN to perform track work on the line, which would "mitigate, but not eliminate", heat-related slow orders. The suspension was originally intended to end on June 29; however, in early June it was extended to mid-September. Service resumed on September 9 with track work not completed. The
Adirondack and were combined between New York and Albany–Rensselaer beginning November 10, 2024, due to construction work in the
East River Tunnels limiting capacity at Penn Station. This was reversed effective December 2, 2024, through at least March 2025. == Operation ==