The equipment will be prescribed as part of the regulations. In broad terms, we're talking about locomotives operating on main tracks to distinguish from equipment that's operating in rail yards where they're marshalling trains and moving trains around. It's mainline track.
Evidence of meeting #67 for Transport, Infrastructure and Communities in the 42nd Parliament, 1st Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was c-49.
A video is available from Parliament.