The Townline Tunnel is an underwater tunnel in

Welland Welland is a city in the Regional Municipality of Niagara in Southern Ontario, Canada. As of 2021, it had a population of 55,750. The city is in the centre of Niagara and located within a half-hour driving distance to Niagara Falls, Niagara-on ...

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

carrying Highway 58A as well as the

Canadian Pacific Railway The Canadian Pacific Railway () , also known simply as CPR or Canadian Pacific and formerly as CP Rail (1968–1996), is a Canadian Class I railway incorporated in 1881. The railway is owned by Canadian Pacific Kansas City, Canadian Pacific Ka ...

under the

Welland Canal The Welland Canal is a ship canal in Ontario, Canada, and part of the St. Lawrence Seaway and Great Lakes Waterway. The canal traverses the Niagara Peninsula between Port Weller, Ontario, Port Weller on Lake Ontario, and Port Colborne on Lak ...

The tunnel

The Townline Tunnel is a two-cell

reinforced concrete Reinforced concrete, also called ferroconcrete or ferro-concrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ...

tunnel with a rectangular cross-section. The roof is a post-tensioned concrete slab. The tunnel was built as a part of the Welland By-Pass project. Its construction was relatively easy since, like the Main Street Tunnel, it was being built at the same time as the channel above it and a simple cut and cover method could be used. The tunnel provides a sidewalk for pedestrians, two lanes for vehicular traffic, as well as room for three sets of tracks for rail vehicles. It was opened for automobiles on July 13, 1972, and the first train crossed the tunnel on January 31, 1973. The tunnel is 330 metres (1083 ft) long and 35 metres (115 ft) wide. The low grade required for trains makes necessary that each approach to the tunnel stretch be 4 km (2.5 miles). There was removed about 13,750,000 cubic meters (18,000,000 cubic yards) of material and construction of three

viaduct A viaduct is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide ...

s on each side of the canal. As well, a solid earth plug had to be put into the Welland Recreational Waterway (the old alignment of the canal), cutting it in two
satellite photo
. The construction cost was $40 million. The middle rail line was removed in the 1990s and the two remaining tracks now serve as the CPR Hamilton Subdivision and the CPR Brookfield Siding. Townline Tunnel is known locally as the "Stinky Tunnel" due to the strong odor of rotten eggs as one passes through it. The distinct smell of

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...

that is sometimes present in the tunnel is created by dissolving layers of gypsum which are present in the bedrock of the area.

Issues with Flooding Control

Rain and snow falling on the approaches to the tunnel, as well as ground water flow, necessitate the operation of a pumping system to prevent flooding. Water is pumped via pipes located under the road and discharged into the canal. In February 1985, excessive runoff during a winter thaw caused flooding in the tunnel which closed the route to both rail and vehicular traffic. In late March, 2010, a routine inspection of the concrete pipes through which the water is pumped revealed erosion which threatened to cause a sinkhole within the road. The tunnel was closed to vehicular traffic to allow for repair. It re-opened April 22.

External links

Newspaper clippings about the tunnel's construction

References

{{Crossings navbox , structure = Crossings , place =

, bridge = Townline Tunnel , bridge signs = , upstream =

Highway 3 The following highways are numbered 3, H-3, PRI-3, AH3, E03 and R3. For roads numbered A3, see A3 roads. For roads numbered M3, see M3 (disambiguation)#Roads, M3. For roads numbered N3, see N3 (disambiguation)#Roads, N3. For roads numbered 3A, see ...

/Main Street Lift Bridge (

Port Colborne Port Colborne is a city in Ontario, Canada that is located on Lake Erie, at the southern end of the Welland Canal, in the Niagara Region of Southern Ontario. The original settlement, known as Gravelly Bay, dates from 1832 and was renamed after ...

) , upstream signs = , downstream = Main Street Tunnel,
Canboro Road ( Former Hwy 20),
Thorold Tunnel ( Highway 58) , downstream signs = Canadian National Railway tunnels Railway tunnels in Ontario Road tunnels in Ontario Welland Canal Buildings and structures in Welland Transport in Welland Rail transport in Welland Tunnels completed in 1972 1972 establishments in Ontario