Notwithstanding that is exactly not what you said:
Outside of the the major urban centres, much of the proposed HxR alignment is essentially greenfield in terms of things like land ownership and modern infrastructure. They will be able to exploit things like existing blastings, grade fill, etc. but I'm not aware that any of the ROW, certainly between Smiths Falls and Havelock has been set aside or land banked. I do believe much of it is a train (of unknown ownership) and carries a telco easement (but I don't know if even that is current).