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The Thorold Tunnel

The Thorold Tunnel is located in the city of Thorold, in the Niagara Region of Ontario. The underwater tunnel was built between 1965 and 1967, and allows Highway 58 to cross the Welland Canal without interrupting shipping.

Photo of Thorold Tunnel 2009

The tunnel was constructed in stages. The Canal section was constructed during the winter months when the Canal was drained. A trench was dug, and concrete sections shaped like tubes were poured to form the tunnel. During the summer months, the end sections of the tunnel were constructed, allowing shipping to continue. A sidewalk was built on the westbound side of the tunnel, allowing access to pedestrians through the tunnel.

The air in the tunnel is constantly monitored for carbon monoxide and, if needed, using an elaborate fan system, can be changed within 20 seconds. The lighting in the tunnel is controlled by photosensors that operate the lights in stages to provide light levels comparable to those outside the tunnel. This is to reduce the chances of being blinded by a dark tunnel, or emerging from a well-lit tunnel into the darkness of night. Traffic signals are mounted to the ceiling to control traffic during maintenance or emergency situations within the tunnel.

For more information on the Thorold Tunnel, contact Daniel Saint-Laurent at (905) 227-5516.

Technical Information:

  • Length - 840 metres (or .84 kilometres)
  • Height - 4.5 metres
  • Lanes - two westbound, two eastbound
  • Speed - 80 km-h
  • Roof thickness - 1.8 metres of reinforced concrete
  • Wall thickness - 1.5 to 1.8 metres of reinforced concrete, covered with epoxy paint
  • Lighting - 2,300 HPS lamps
  • Traffic volume - 24,300 vehicles pass through the tunnel daily

You can view images from traffic cameras in and around the Thorold Tunnel here (scroll to the bottom of the map).