Substantial delays crossing the international border after the September 11th attacks, combined with freight congestion and the 2003 SARS outbreak, drastically reduced ridership.

The Grand Trunk Railway opened its St. Clair Tunnel between Sarnia, Ontario and Port Huron, Michigan in 1891, completing the first direct all-rail route from Chicago to Toronto and Montreal.

[1][2] The Canadian National Railway (CN) and Grand Trunk Western Railroad (GTW) introduced the International Limited on May 25, 1900.

GTW and parent company CN used aggressive marketing, inexpensive fares, and on-board perks like free meals to attract riders.

After Via Rail took over Canadian intercity passenger services in 1978, Amtrak saw a chance to improve the Blue Water Limited's financial performance by extending it to Toronto.

Negotiations soon reached a stalemate; Michigan desired a later Sunday schedule so that weekend travelers to Toronto could return late in the evening, but Via did not.

[12] The New York-Toronto Maple Leaf, introduced in April 1981, had proved an immediate success, and Amtrak and Via soon reached an agreement to extend the Blue Water Limited to Toronto as well.

Michigan funded a Flint-Battle Creek bus, which connected with the westbound Wolverine and eastbound Twilight Limited, to preserve Flint-Chicago day trips.

In contrast to its predecessor, it used ex-Penn Central trackage west of Battle Creek, Michigan—in common with Amtrak's other Michigan trains—and ran on a daylight schedule.

[15] In 1995, during a funding crunch, Amtrak proposed routing the International through Durand, Pontiac, and Detroit, thus dropping Flint and Port Huron.

[16] Detroit station would have been skipped entirely; Amtrak would no longer have used state funds for the International, though they may have been used for a replacement Port Huron train instead.

[17] After the September 11 attacks, security personnel were redeployed to the Blue Water Bridge, and U.S. Customs refused to continue on-board screenings.

[17] The security issues caused massive delays, even after on-board screening resumed on February 19, 2002, amid complaints from the state and both railroads.

[17] Delays caused by the border crossing and freight congestion continued to erode ridership, as did the 2003 SARS outbreak in Toronto.

Via retained a single daily Toronto-Sarnia round trip that was merged into its Corridor service, but a planned Port Huron-Sarnia bus was never implemented.

The Horizon Fleet was substituted beginning in 2000 to allow the Superliners to add capacity to western trains, and Genesis locomotives were used in the final years.