Idaho Const. art. XI, § 5

All railroads shall be public highways, and all railroad, transportation, and express companies shall be common carriers, and subject to legislative control, and the legislature shall have power to regulate and control by law, the rates of charges for the transportation of passengers and freight by such companies or other common carriers, from one point to another in the state. Any association or corporation organized for the purpose, shall have the right to construct and operate a railroad between any designated points within this state, and to connect within or at the state line, with railroads of other states and territories. Every railroad company shall have the right with its road, to intersect, connect with, or cross any other railroad, under such regulations as may be prescribed by law, and upon making due compensation.