UPSC CAPF AC 2021 Paper

The heaviest rocks, which are rolled along the river bed in river transport, come under Traction load.
Bed load, sometimes referred to as traction load, is the material that is transported by sliding,rolling, and saltating (skipping) along the bed of a stream. Particles comprising bed load can range in size from sand to boulders. The movement of bed load is responsible for bed forms that change in time and space along a stream bed.