JérômeOntario regional train return to the North announced their pricing
https://www.cbc.ca/news/canada/sudbury/northlander-fares-ontario-9.7157717
It will be the second passenger rail line by the Ontario Northland Railway
They already operate the "Polar Bear Express" all the way to James Bay, which is arguiably the best name for a train service.
https://en.wikipedia.org/wiki/Polar_Bear_Express
So you should be able to go from Toronto to Cochrane on the Northlander, then transfer to the Polar Bear Express to Moosonee.
