Various attachments (different dozer blade arrangements, a gantry crane, large auger) are designed for use with multiple identical powered mobile modules including a main support frame housing an internal combustion engine as a prime mover and being supported on either powered tracks or wheels. The modules can be either equipped with a cab and manned or used without a cab and controlled remotely. One or more of the mobile modules may be equipped with a GPS unit to aid in positioning the associated attachment.