The current subject matter describes a device and system including one or more movable arms containing one or more magnets that are caused to move relative to a non-ferrous material by motion of the device to generate eddy currents that cause a braking of the device. Devices of this disclosure may include one or more trolleys that moving along a coaster track and which contain braking arms having magnets that move due to inertial force and/or can be controlled by a remote server computer based on information obtained from the one or more trolleys as they move along the coaster track.