Amtrak's Adirondack has been plagued for years by extensive border delays in both directions to its New York-Montreal journey due to both U.S. and Canadian customs clearance procedures. Now, spurred by U.S. Sen. Charles Schumer (D-NY), the railroad and both nations may be able to reduce delays.
Article is here.
Still unclear is whether any U.S.-Canada agreement would also pertain to Amtrak's Maple Leaf, running between New York and Toronto, which crosses the border at Niagara Falls, N.Y., and its namesake sister city in Ontario.
It's entirely clear to me. Pre-clearance would not be possible on the Maple Leaf -- not unless the train ran nonstop from Niagara Falls, NY to Toronto. But since it functions as one of the 2 daily VIA Rail frequencies between Niagara Falls, ON and Toronto, it is not a closed environment. Plus, customs facilities in Niagara Falls, NY are being relocated and refurbished, which makes a move of the function to Toronto even less likely.