Actually this TIGER grant is primarily about freight, as this is part of the designated New England - Canada freight corridor. It's title is Northern Vermont Freight Rail Project. It is about upgrading the St. Albans - Canadian Border segment to 286k standard (i.e. able to carry 286 klb freight cars). The Project Description says:
The tracks are still used for trains, as I understand it, it's not like the route is gone. But passenger trains require a little higher standard.
TIGER funds will upgrade 18.8 miles of railroad track between St. Albans, Vermont, and the Canadian border.
The upgrades will enable the track to carry the gross rail weight standard of up to the 286,000 pounds, allowing
more efficient movement of goods throughout the region and internationally.
The advantage provided to passenger service is listed as a secondary benefit that accrues from this work