(a) On or before May 1 in each year a return in writing shall be filed with the board of public works: (1) By the owner or operator of every railroad, wholly or in part, within this state; (2) by the owner or operator of every railroad bridge upon which a separate toll or fare is charged; (3) by the owner or operator of every car or line of cars used upon any railroad within the state for transportation or accommodation of freight or passengers, other than the owners or operators as may own or operate a railroad within the state; (4) by the owner or operator of every express company or express line, wholly or in part, within this state, used for the transportation by steam or otherwise of freight and other articles of commerce; (5) by the owner or operator of every pipeline, wholly or in part, within this state, used for the transportation of oil or gas or water, whether the oil or gas or water be owned by the owner or operator or not, or for the transmission of electrical or other power, or the transmission of steam or heat and power or of articles by pneumatic or other power; (6) by the owner or operator of every telegraph or telephone line, wholly or in part, within this state, except private lines not operated for compensation; (7) by the owner and operator of every gas company and electric lighting company furnishing gas or electricity for lighting, heating or power purposes; (8) by the owner or operator of hydroelectric companies for the generation and transmission of light, heat or power; (9) by the owner or operator of water companies furnishing or distributing water; and (10) by the owner or operator of all other public service corporations or persons engaged in public service business whose property is located, wholly or in part, within this state.

(b) The words "owner or operator," as applied herein to railroad companies, shall include every railroad company incorporated by or under the laws of this state for the purpose of constructing and operating a railroad, or of operating part of a railroad within this state, whether the railroad or any part of it be in operation or not; and shall also include every other railroad company, or persons or associations of persons, owning or operating a railroad or part of a railroad in this state on which freight or passengers, or both, are carried for compensation. The word "railroad," as used herein includes every street, city, suburban or electric or other railroad or railway.

(c) The words "owner or operator," as applied herein to express companies, shall include every express company incorporated by or under the laws of this state, or doing business in this state, whether incorporated or not, and any person or association of persons, owning or operating any express company or express line upon any railroad or otherwise, doing business partly or wholly within this state.

(d) The return shall be signed and sworn to by the owner or operator if a natural person, or, if the owner or operator shall be a corporation, shall be signed and sworn to by its president, vice president, secretary or principal accounting officer.

(e) The return required by this section of every owner or operator shall cover the year ending on December 31, next preceding, and shall be made on forms prescribed by the board of public works, which board is hereby invested with full power and authority and it is hereby made its duty to prescribe the forms as will require from any owner or operator herein mentioned information as in the judgment of the board may be of use to it in determining the true and actual value of the properties of the owners or operators.