Wooden coasters: towering, majestic, beautifully designed, classic. But the same woodies that look so wondrous from afar can be rickety, shaky and head-jangling to ride. As trains wear down their wood tracks, a coaster that was once smooth becomes more and more difficult to handle over time. How do you solve the problem? The answer used to be to call in experts to repair the tracks. But now park owners are turning to a new option: replacing the wood tracks with bendable, pliable steel, and turning the coaster into a thrilling hybrid.

One company in northern Idaho, Rocky Mountain Construction, has forged a business out of this practice and, in the process, has become responsible for turning a handful of existing wooden coasters into some of the most thrilling, contemporary and innovative rides in the coaster world. The rides often keep much of their look intact, maintaining a lot of the wood that makes up their basic structure, but now running through them is a sleek, shiny, colorful steel track that stands out from the wood and makes the overall attraction feel more 21st century.

A signature project by the company, founded by Fred Grubb and Suanne Dedmon 15 years ago, is its rehabilitation of Colossus, a giant white wooden coaster near the parking lot at the edge of Six Flags Magic Mountain in Valencia, Calif. The dual-track racing coaster had been a staple at the park since 1978, thrilling generations of riders, and undergoing generations of wear and tear.