In addition to bringing Yellow Pages-powered business listings to Apple Maps customers in Canada, the Cupertino firm has apparently refreshed a Maps backend in the United States, adding transit directions for Boston and multiple Amtrak routes in the Northeastern United States.
The longest Amtrak route available runs from Chicago to New York. As first noted by MacRumors, other supported routes with transit directions include the Northeast Regional, Acela Express, Keystone, Lake Shore Limited, Pennsylvanian and Maple Leaf.