(a) All the provisions of this act shall apply to and include all persons, companies, or corporations carrying property on any railroad as express matter and known as express companies, as fully as if the persons, companies, or corporations were specially named and designated in this act.
(b) All the provisions of this act shall apply to all property and all the services in and about the transportation thereof on one (1) actually or substantially continuous carriage, or a part thereof, and to the compensation therefor, whether the property is carried wholly on one (1) railroad or partly on several railroads and whether the services are performed or compensation paid or received by, or to, one (1) person or corporation, alone, or in connection with another or other persons or corporations.