I checked out SH. Great rumour and if the railroad construction is true it would make a lot of sense that it would be for hauling ore. The only other reason for this railroad would have been logging which is pretty much extinct from what I understand.
I wouldn't rule out Bowmore (osisko) as having something to do with this. Malartic is in the midst of achieving full-scale production and they would be looking for the 'next thing' to put their considerable resources towards. I think Osisko has secured several properties but let's face it, if anyone is capable and experienced in navigating the politics and construction of a gold mine in Quebec, it's them.
This serves as a reminder as how infrastructure in this region already exists in 'too good to be true' form.