Steam locomotives were used in the early years to pull trains through the tunnel, however concerns about the potential dangers of suffocation should a train stall in the tunnel led to the installation of catenary wires for electric-powered locomotives by 1907.
The first use of electric locomotives through the tunnel in regular service occurred on May 17, 1908.
The locomotives were built by Baldwin-Westinghouse.

In 1923, the GTR was nationalized by Canada's federal government, which then merged the bankrupt railway into the recently formed Canadian National Railway.
CN also assumed control of Grand Trunk Western as a subsidiary and the tunnel company and continued operations much as before.

The electric-powered locomotives were retired in 1958 and scrapped in 1959 after CN retired and scrapped its last steam-powered locomotives on trains passing through the tunnel.
New diesel-powered locomotives did not cause the same problems with air quality in this relatively short tunnel.
Steam locomotives were used in the early years to pull trains through the tunnel, however concerns about the potential dangers of suffocation should a train stall in the tunnel led to the installation of catenary wires for electric-powered locomotives by 1907. The first use of electric locomotives through the tunnel in regular service occurred on May 17, 1908. The locomotives were built by Baldwin-Westinghouse.
In 1923, the GTR was nationalized by Canada's federal government, which then merged the bankrupt railway into the recently formed Canadian National Railway. CN also assumed control of Grand Trunk Western as a subsidiary and the tunnel company and continued operations much as before.
The electric-powered locomotives were retired in 1958 and scrapped in 1959 after CN retired and scrapped its last steam-powered locomotives on trains passing through the tunnel. New diesel-powered locomotives did not cause the same problems with air quality in this relatively short tunnel.
St. Clair Tunnel