Based on the principle of a baby top model gyroscopic railway.
The structure of the gyroscopic railway is clear from the figure. The platform, inside which the massive flywheel rotates quickly, moves along one rail - and does not fall!
The stability is attached to it by the gyroscopic property of the flywheel. It is untwisted with the help of a thread. On one axis with it is a rubber roller, which is pressed against the rail. He then creates cravings.
Models of such railways are usually performed in the form of a horizontal wire ring mounted on poles. Trains can ride on a cable.