Carrier rig:

A large, specially designed, self-propelled workover rig that a person drives directly to the well site.

Power from a carrier rig’s hoist engine or engines also propels the rig on the road.

While a carrier rig is primarily intended to perform workovers, it can also be used to drill relatively shallow wells.

A carrier rig may be a back-in type or a drive-in type.

See back-in unit, drive-in unit.