The way the definitions are done is by the revenue they make with the amount of tonnage. If you have what I'll call a “holding company” that holds various railways that operate across the country, in some cases those railways may be under federal jurisdiction, and in other cases they may be under provincial jurisdiction. They're not operating as one company, but operating separately under what I'll call a “franchise”, differently. The classification is really based on those revenues and the activity that the companies generate.
On September 11th, 2017. See this statement in context.