Slow Boat

Humans have invented four different kinds of locks for use on canal systems.  One of the cool things about Canada's Trent - Severn Waterway is that it has all four kinds:  1) conventional locks, where water goes in, and your boat floats up; 2) flight locks (that's two or more conventional locks, all in a row); 3) lift locks (see our entry for the Peterborough Lift Lock); and 4) marine railways.

And here's what it looks like as your boat is being loaded onto a marine railway, the Trent-Severn's "Big Chute Railway."  See the white motor boat? our boat is just behind it, loaded onto its own set of sling straps.

The railway carries as many as 6 boats over a hill, in the process helping boats avoid a narrow and turbulent stretch of river called the Big Chute, where water flows fast down a rocky canyon.