An excavator is a diesel-powered construction machine used for digging out the earth with a bucket. Excavators are mainly used for digging, but other attachments give them the capability to clear brush, load, dump, and demolish. Most excavators are tracked, but some models have wheels. Excavators are comprised of a cab, engine, boom, digging arm, and attachment (usually a bucket). Excavators can dig between 10 to 48 feet deep and are stable on slopes.