On the slope, most toboggans attempt to brake and steer with simple rear-mounted lever brakes.
On the slope, most toboggans attempt to brake and steer with simple rear-mounted lever brakes.

What's cold, weighs 300 pounds, has 10 legs (possibly broken), and reaches top speeds of 50 to 70 kilometers per hour before grinding to a halt, overturning, or colliding with an obstacle? If you guessed "A concrete toboggan," you're right. If you said, "There is no such thing as a concrete toboggan," you are mistaken. In fact, dozens of concrete toboggans and more than a hundred intrepid tobogganauts compete each year in Canada's annual Great Northern Concrete Toboggan Race, a unique test of the athletes' imagination, technical skill, and raw courage.

Inspired by the concrete-canoe races sponsored by the American Society of Civil Engineers, the concrete-toboggan race attracts a very special breed of north-country engineering students. The basic principle is simple: Whoever slides fastest, wins. There are a few rules, however. The sleds must have a concrete sliding surface, weigh no more than...

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