Tuesday, July 26, 2016

Portage Lake Lift Bridge between Houghton and Hancock, MI

(Bridge Hunter, Historic Bridges, Streetview, Google Photo)

These screenshots are from a video of the construction of the lift bridge that replaced a swing bridge that had just 5-feet of clearance and took a long time to open and close. So traffic backups through the two towns were common. The bridge has two decks. Originally the upper deck of the approaches carried vehicles and the lower deck carried railroads. Normally, the lower deck of the lift span is aligned with the vehicle deck of the approach spans to provide a 32-foot clearance that allows most pleasure craft and fishing boats to pass without stopping traffic as depicted by the first screenshot. The second screenshot shows the lift span lowered so that both vehicle and railroad traffic can cross.

The full height provides a clearance of 100 feet. This video of the bridge going up and down is made from three perspectives: from a boat, from the shore, and from a pedestrian crossing.

Looking at a railroad map, there used to be a lot of routes and mining shafts on the peninsula. ALL of the routes are now abandoned. Since there is no boat traffic in the winter, the span is down all winter and the lower deck is now used for snowmobiles. By the time of the abandonments, all the routes were owned by SOO (Minneapolis, St Paul & Sault Ste Marie)

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