From its north end, CSX has trackage rights west over the Canadian National Railway's Strathroy Subdivision (through the St. Clair Tunnel) and the Grand Trunk Western Railroad's Flint Subdivision to the CSX Port Huron Subdivision near Port Huron, Michigan, and the Saginaw Subdivision in Flint.
CSX has access from its northern end westward over the Canadian National Railway's Strathroy Subdivision (through the St. Clair Tunnel) and the Grand Trunk Western Railroad's Flint Subdivision to the CSX Port Huron Subdivision near Port Huron, Michigan, and the Saginaw Subdivision in Flint.