The towed scraper consists of a scraper bowl which is towed by a wheeled tractor or by a bulldozer. The lowering and lifting of the cutting edge of the bowl is controlled either by ropes or hydraulically. If the bowl is rope-operated, it is supported on two axles running on four wheels. However, if the bowl is hydraulically operated, it is supported on one axle running on two
wheels. A powerful tractor (or bulldozer) with a power unit of kW or more and fitted with specially strong and deep webbed crawler tracks or large wheels is required to provide the necessary traction. The speed of the excavation depends on the speed of the tractor. The tractor moves at a relatively slow speed of about 3 to 10 km/h.
Towed scrapers are favoured for short hauls of about 300 m. They have the ability to excavate on the upward gradientm, to manoeuvre and turn within a small working area, to load in
heavy soil, and to 'pump' load in patches of hard soil