A system for tensioning and locking a safety strand to a number of sequentially arranged stanchions is provided. The system includes tensioning means for applying a tensile force to one end of the safety strand when the safety strand is passed through a passage bore of each of the sequentially arranged stanchions and the other end of the safety strand is secured to an immovable object. Locking mechanisms are provided that each include a cable cradle having a receiving channel for receiving a portion of the safety strand, a clamping arrangement for engaging and trapping the portion of the safety strand within the receiving channel, and a device for securing the cable cradle and clamping arrangement to a stanchion. The cable cradle and securing device are configured so that when the cable cradle is secured to the selected stanchion, the receiving channel is in registry with the passage bore.