A Boeing 757 brake, for example, has 3 stators and 4 rotors.[74] The Space Shuttle also uses frictional brakes on its wheels.[75] As well as frictional brakes, hybrid/electric cars, trolleybuses and electric bicycles can also use regenerative brakes to recycle some of the vehicle's potential energy.[44] High-speed trains sometimes use frictionless Eddy-current brakes; however widespread application of the technology has been limited by overheating and interference issues.[76]