Here is more on gyroscopic monorails. Louis Brennan patented his design in 1903 and demonstrated a full-scale monorail car able to carry 50 passengers at the Japan-British Exhibition in London in 1910. In addition to requiring only one rail, the gyroscopic stabilisation mechanism causes the car to automatically bank while turning, eliminating centrifugal acceleration for passengers and cargo on board without the need for complex machinery as in present-day tilting trains. The main disadvantage is that all cars in a train would require their own gyroscopes to maintain stability.