Since beginning service in 1967, GO Trains have operated on tracks owned primarily by Canada's two major commercial railways: Canadian National Railway (CN) and Canadian Pacific Railway (CPR).

Over the past several years, Metrolinx has been acquiring segments of the rail lines on which GO Trains travel. Ownership of the tracks and adjacent property allows for control over maintenance and expansion work.

Currently, Metrolinx owns 69% of the GO Train corridor network, and work is already underway to prepare the infrastructure for more passenger rail service in the coming years.