A Massachusetts-focused webpage blames track work in southern VT for delaying the southbound Vermonter. Presumably it also affects the northbound, but they don’t worry about that as that train has already served western Mass.

> Service Advisory | Late Southbound Vermonter > > The southbound Vermonter — Amtrak trains 55 and 57 — has been departing up to an hour late from Greenfield, Holyoke and Northampton due ongoing track work in southern Vermonter. At this time we do not know when the track work will be completed.