Steel rope suspended in a vertical shaft to prevent excessive swinging of the cages or skips. Eight rope guides are generally used for the shaft, four for each cage, and two additional rubbing ropes are installed to prevent possible collision between the cages or skips. The ropes are suspended from girders fixed on the safety hook catch-plate platform and kept taut in the shaft by means of weights in the shaft bottom sump. The clearances between the cages, and also between the cage corners and the shaft wall, should be about 12 in (30.5 cm).