Cable cars, such as those famously found in San Francisco, do not have their own onboard engines to generate movement. Instead, they operate by "gripping" a continuous steel cable that runs at a constant speed beneath the street. To slow down or stop, the operator (known as a "gripman") must first release the tension on this cable by moving a large manual lever, effectively disconnecting the car from its power source. Once the car is coasting, the braking process involves three distinct mechanical systems. The first is the wheel brakes, operated by a foot pedal, which apply friction to the wheels like a standard train. The second is the track brakes, controlled by a hand lever, which press large wooden blocks directly against the rails to create friction. In extreme cases or steep inclines, an emergency brake can be deployed, which drops a steel wedge into the cable slot to stop the car instantly. Because the cable itself never stops moving, the art of slowing down a cable car is a manual balancing act of releasing the grip at just the right moment while applying physical force to the wooden and metal brake shoes.