been found to be common carriers; a famous example is Disneyland. Regulatory bodies may also grant carriers the authority to operate under contract with their customers instead of under common carrier authority, rates, schedules and rules. These regulated carriers, known as contract carriers, must demonstrate that they are "fit, willing and able" to provide service, according to standards enforced by the regulator. However, contract carriers are specifically not required to demonstrate that they will operate for the "public convenience and necessity." A contract carrier may be authorized to provide service over either fixed routes and schedules, i.e., as regular route carrier or on an ad hoc basis as an irregular route carrier. It should be mentioned that the carrier refers only to the person (legal or physical) that enters into a contract of carriage with the shipper. The carrier does not necessarily have to own or even be in the possession of a means of transport. Unless otherwise agreed upon in the contract, the carrier may use whatever means of transport approved in its operating authority, as long as it is the most favorable from the cargo interests' point of view. The carriers' duty is to get the goods to the agreed destination within the agreed time or within reasonable time. The person that is physically transporting the goods on a means of transport is referred to as the "actual carrier." When a carrier subcontracts with another provider, such as an independent contractor or a third-party carrier, the common carrier is said to be providing "substituted service." The same person may hold both common carrier and contract carrier authority. In the case of a rail line in the US, the owner of the property is said to retain a "residual common carrier obligation," unless otherwise transferred (such as in the case of a commuter rail system, where the authority operating passenger trains may acquire the property but not this obligation from the former owner), and must operate the line if service is terminated. In contrast, private carriers are not licensed to offer a service to the public. Private carriers generally provide transport on an irregular or ad hoc basis for their owners. Carriers were very common in rural areas prior to motorised transport. Regular services by horse-drawn vehicles would ply to local towns, taking goods to market or bringing back purchases for the village. If space permitted, passengers could also