Map locating Detroit's vehicular and rail tunnels. photo credit |
Ferry carries rail cars across the Detroit River circa 1900 photo credit |
The tunnel was the first built without compressed air. It was constructed using an engineering method known as Immersion Tube. The method is cheaper and faster than boring into the Earth and is simple in concept:
- Dig a 13 foot deep trench in the Detroit River bottom
- Float bulkheaded sections of the steel tunnel tube (263 feet (80 meters) long) into place
- Sink the sections into the trench with weights
- Align the new section with the previously sunk section
- Drain the water between the sections
- Seal the connection
- Backfill the trench and connected tube sections with concrete
- Pump the steel tubes dry
- Finish the inside of the steel tube with 1.5 feet (50 cm) thick concrete
the Stages of Immersion Tube Construction Image Credit (figure 4) |
Steel tubes being floated into place along the Detroit River photo credit |
The Detroit River Tunnel Company built the tunnel for $8.5 million. It was constructed under the supervision of the New York Central Railway's Engineering Vice President, William J. Wilgus.
Seven workmen operating machinery while building the Michigan Central Railway Tunnel, 1907. photo credit |
Beginning in August 1992, the tunnel's north tube underwent a $27 million enlargement to permit the passage of stacked container railcars and multilevel auto carriers railcars. Rivaling the engineering of the original design, the enlargement involved the removal of a portion of the concrete ceiling, floor and sides. The link below contains a video describing the history of the tunnel as well as details of the expansion project:
The tunnel today continues to handle an annual volume of approximately 400,000 railcars.
Entrance into the Detroit side of Michigan Central Railway Tunnel photo credit |
Closer detail of Detroit side entrance. Note that the left tunnel's ceiling and side walls have been modified to accept taller and wider rail cars. photo credit |
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Gleit, Jon, "The Detroit River Tunnel Few Have Seen: The Michigan Central Railway Tunnel", April 12, 2016, Detroit Historical Society.
Lee, Ardelia, "The Other Detroit River Tunnel No One's Told You About", July 9, 2016, Daily Detroit.