My helix is finally operational after 4 years of trial and error, but only part time. I made the first trial run in February and after getting a few bugs out it was ready for the open house held May 11th. The width is 18ft. using Lionel 0-60 Fastrack going up and Lionel 0-54 tube rail for the down side. The cable bridge is aprox 6 ft. long, the top bridge is a little longer and using 0-72 track.