These are neat but I wonder what sort of safety is implemented to prevent a freefall. There's usually a braking system, but the cabs aren't generally affixed to the walls of the shaft. They're just resting on a guide with the safety coming from the rope and the rope gripper system. And the buffers at the bottom aren't usually rated for freefall, they're there to take a hit from a normally operating cab that doesn't stop. One issue this solves is the less commonly considered scenario where the counterweight falls and sends the cab flying up.