Clamped carriages lock to the skyline during log pickup. The clamping may be done by a hand-actuated clamp, as shown below, or may clamp through a spring loaded release that hits a "stopper" button positioned on the skyline, or through a radio-controlled clamp on a self-propelled carriage.

Clamped carriages transfer the entire weight to the skyline when the logs are lifted at pickup, unlike unclamped carriages, which share the load between the skyline, haulback, and mainline(s).