The rope-drum system used in the old elevators is replaced by an electric motor instead of the steam machine. But most of the electric elevators are now drawable. In these elevators, one end of the suspension ropes is connected to the elevator car, and the other end to a counterweight that balances the weight of the cabin. Each of the hanger ropes sits on a hoist placed on the top of the elevator shaft or on a separate yacht on the reel. This reel, driven by an electric motor, rotates the ropes as it rotates. Thus, while the elevator is traveling in one direction, the counterweight moves in the opposite direction. Today's elevators are equipped with many security systems that prevent the cabin from moving too fast and reaching the top or bottom floor level and crossing the top or bottom floor level. Even if these devices do not work, it is impossible for the elevator to pass through the top floor and rise to the height of the devices at the top. Because when the cabin reaches the top, the counterweight sits on the bumpers in the bottom of the well so that the ropes can not pull up the cabin because it loosens. Some modern elevators are piston-electric type. They work just like the old hydraulic elevators, only oil is used instead of water to prevent rusting and freezing. The oil pressurized by the electric pump is discharged into the cylinder. These elevators are used in non-high-lift structures, especially for lifting heavy loads in factories and on elevator platforms of aircraft wagons and car wash-lubrication stations.