An excavator, also called a 360-degree excavator or digger, sometimes abbreviated simply to a 360, is an engineering vehicle consisting of a backhoe and cab mounted on a pivot (a rotating platform, like a Lazy Susan) atop an undercarriage with tracks or wheels. Their design is a natural progression from the steam shovel.
Note: the term excavator is sometimes used as a general term for any piece of digging equipment. Tracked excavators are sometimes called trackhoes.
Excavators come in a wide variety of sizes. The smaller ones are called a mini-excavator or compact excavator. One manufacturer's largest model weighs 84,980 kg (187,360 lb) and has a maximum bucket size of 4.5 m³ (5.9 yd³). The same manufacturer's smallest mini-excavator weighs 1470 kg (3240 lb), has a maximum bucket size of 0.036 m³ (0.048 yd³) and the width of its tracks can be adjusted to 89 cm (35 inches). Another company makes a mini excavator that will fit through a doorway with tracks that can be adjusted to only 70 cm (28 inches) wide.
Often the bucket can be replaced with other tools like a breaker, a grapple or an auger. Excavators are usually employed together with loaders and bulldozers. Most smaller excavators have a small backfill (or dozer-) blade. This is a horizontal bulldozer-like blade attached to the undercarriage and is used for pushing removed material back into a hole.