Freestanding anchors are used near edges or in open spaces when surface penetration and overhead anchor options are not available. Mast anchors are rolled into place and have a counterweight to form a temporary anchor, and can be moved to a new location as needed. Pole anchors provide a tie-off point around vehicles and machinery. Rail anchors provide an extremely high anchor point and are used around rail cars. Anchor points allow workers to attach a lanyard or self-retracting lifeline (SRL) as part a personal fall protection system when working at height.