Which device travels on a lifeline to arrest the fall of a worker?

The correct answer is the rope grab, which is a device specifically designed to travel along a lifeline and arrest a worker's fall. When attached to a fall protection system, a rope grab moves smoothly along the lifeline during regular movement but locks in place if a sudden fall occurs. This locking mechanism is crucial because it provides immediate support and arrest, helping to prevent or mitigate the impact of the fall.

In the context of fall protection systems used in construction, the rope grab is often combined with a safety harness to ensure that a worker is secure and protected at heights. Understanding the function of a rope grab highlights the importance of having systems in place that allow for both mobility and safety when working at elevated levels.

The other devices mentioned, such as safety harnesses, deceleration devices, and shock absorbers, play important roles in fall protection but do not specifically serve as traveling devices on a lifeline. A safety harness secures the worker and distributes fall forces, while a deceleration device helps slow down the fall and reduce impact forces. Shock absorbers are designed to manage the forces experienced by a worker during a fall, but they are not designed to move along a lifeline like a rope grab does.