Wheel tractor-scraper !!! In civil engineering, a wheel tractor-scraper is a piece of heavy equipment used for earthmoving. Types of Scraper Single engine open bowl (standard tractor arrangement-usually needs a bulldozer to assist in loading) Single engine elevating scraper (using elevator to load material and needs no push tractor) Twin engine open bowl (the two engines means usually no push tractor is required) Twin engine push-pull (uses all 4 engines by hooking both scrapers together while loading) Twin engine auger scraper (uses giant auger mounted vertically in bowl to pull material upwards) Pull type scraper (uses agricultural tractor, articulated dump truck, or bulldozer to pull)