Well, a key thing, as Murad has alluded to, is icebreaking on the Great Lakes. Also, the St. Lawrence Seaway has limited capacity in terms of big, competitive ocean-going shipping these days. The ships are getting so much bigger.
My own view is that, over multiple decades, the rail links to ports like Montreal can sustain an increase in shipping, and eventually an increase in product flow through the St. Lawrence. My guess is that doing it through the Great Lakes for the long haul is probably not going to happen. There may be an increase in short sea shipping and some modest increase on the lakes, but having a supply chain that is not 24/7, 365 days of the year is really not going to be competitive in the global economy going forward. You have to have those ground rail links right from the west to tidewater in Quebec or Atlantic Canada.