More than 100 years ago a rail freight tunnel opened beneath the Detroit River between Windsor, Ontario, and Detroit. It was the first successful trench-and-tube tunnel ever constructed in the world, 1.6 miles- (2.6km-) long and originally designed for electric trains.

The Windsor-Detroit corridor accounts for nearly 30 per cent of the total Canada-US trade. The current tunnel carries more than 400,000 rail cars a year, within limits. A proposed modern rail freight tunnel to replace the original would allow for high-clearance rail cars and significantly improve trade between the two countries.

The Continental Rail Gateway (CRG) operates the rail freight tunnel under the Detroit River. It’s a public-private partnership of the Windsor Port Authority, Borealis Infrastructure (a division of the Ontario Municipal Employees Retirement System or OMERS) and Canadian Pacific.

"While this tunnel is in great shape, it is too small for the larger double-stacked 9 feet 6 inch [2.9m] container trains and other modern rail cars," CRG says, It plans to build a replacement rail tunnel adjacent to the existing tunnel.

Once the replacement is completed, all rail traffic, including large rail cars unable to pass through the existing rail tunnel, will be transferred to the new tunnel. Construction could start as early as the first quarter of 2015. The next step hinges on financing, which is coming from a number of directions including two federal governments.

Modern design
Building a replacement tunnel dates back to the early 2000s and the Detroit River Tunnel Partnership, a joint initiative of Borealis Infrastructure Trust and Canadian Pacific. In 2002 it proposed building the larger tunnel and turning the existing tunnel into a cargo truck route. The idea was later scrapped when the US, Michigan and Canadian governments chose to build a new Detroit River bridge.

According to Railway Technology the Detroit River Tunnel Partnership spent around USD 100M on engineering and acquired 20 acres of land for the project from Detroit in 2007. The project has also been called the "Jobs Tunnel" in the period between 2002 and when CRG revived the tunnel in 2010 (see timeline).

For this project a 2.5km-long tunnel will be mined by TBM below the river and parallel, some 45m to the west, to the current tunnel. CRG appointed HDR, MMM Group and Hatch Mott MacDonald as the design and engineering contractor in late 2012.

The proposed replacement rail tunnel will be built at the river depth of 49.2ft (13m), which is about 30ft (9.1m) deeper than the tubes of the existing tunnel. The length of the new tunnel will be 2,845m, which is 700m longer than the existing tunnel, and it will be 500m longer on the Canadian side and 200m longer on the Detroit side. The internal diameter of the tunnel will be 8.4m with a lining thickness of 0.5m.

The tunnel is designed to allow the operation of modern double-stacked large container rail cars with an operating speed of 80kph. Upon completion of the new tunnel, the existing tunnel can be used for passenger trains, which will create a Quebec City to Chicago link.

Money talks
For the most part design, engineering and permitting work has been completed and the necessary environmental assessment approvals secured. There stil remains presidential permit from the Obama administration, and cabinet approval from the federal government of Canada.

The project is estimated to cost USD 400M, which includes building the 2.5km tunnel, installing electrical and mechanical equipment, installing safety equipment and constructing other facilities. The project partners will fund 50 per cent of the project cost and the remaining 50 per cent will come from government sources.

CRG expects to receive USD 10M from the Michigan Department of Transportation, which would leave USD 100M from the Canadian government and USD 90M from the US government.

Size matters
In addition to the 9ft 6in (2.9m) containers there are new generations of multilevel rail cars used by shippers and auto manufacturers. The existing freight tunnel clearance was enlarged once in 1994 and can’t be further expanded, says CRG.

Meanwhile expansion work at the Port of Montreal since 2010 will steadily increase the container traffic out of the port to more than double by 2020.

For Windsor there is the potential for 1,700 – 2,200 direct, indirect, and induced jobs over the duration of development and construction of the tunnel. It also makes the region more competitive as a multimodal center between Canada’s key ports and America’s midwestern markets.

CRG points out the new tunnel will offer an "ideal alternative to trade over highways"