Salt Lake City is getting a new light-rail line for the 2002 Winter Olympics. And to do it, they must dig up and move every water main, gas pipe, and sewer conduit running parallel underneath the two-and-a-half-mile track.
|Stray current corroded these rail spikes in Chicago.Photograph courtesy of Thomas J. Barlo/CC Technologies|
Why? Corrosion. The prob-lem is hardly unique to this rail link, which will connect the main stadium at the University of Utah to downtown. Sometimes stray electrons from the current that powers the train leak into the ground and flow through any pipes or other conductive objects buried there. "One amp going through for one year will corrode about 20 pounds of steel. It can discharge from a small area and penetrate a pipe in a very short time," says Steve Nikolakakos, a corrosion engineer with Russell Corrosion Consultants of New York.
So Salt Lake City's public utilities project is using nonconductive polymer pipe or plastic-sheathed metal pipe. Plastic or rubber pads under the train tracks prevent current leakage. And routine checks of the pipes will pinpoint trouble spots.