Prior to the construction of the tunnel, the Canada Southern Railway had several connections to Michigan at its west end, all train ferries.

In 1891, the Grand Trunk Railway opened the St. Clair Tunnel at Port Huron, giving it an advantage over the Canada Southern and its car ferries.

[2] The north tube underwent a $27 million enlargement in 1993 to allow passage of certain types of modern rail cars such as those with stacked containers and auto carriers, which had been previously ferried across the Detroit River.

[3] In early 2000, CN agreed to sell its stake to Borealis Transportation Infrastructure Trust (a venture of the Ontario Municipal Employees Retirement System) and use only the St. Clair Tunnel.

[6] In 2010, the Windsor Port Authority, Borealis Infrastructure, and CPKC announced plans to construct a new rail tunnel compatible with double-stacked trains.

The initiative, called the Continental Rail Gateway, was scrapped in 2015, upon the approval of the proposed Gordie Howe International Bridge.