Idaho Code § 61-510
Whenever the commission, after a hearing had upon its own motion or upon complaint, shall find that the public convenience and necessity would be subserved by having connections made between the tracks of any two (2) or more railroad or street railroad corporations, so that the cars may readily be transferred from one to the other, at any of the points hereinafter in this section specified, the commission may order any two (2) or more such corporations owning, controlling, operating, or managing tracks of the same gauge to make physical connections at any and all crossings, and at all points where a railroad or street railroad shall begin or terminate or run near to any other railroad or street railroad. After the necessary franchise or permit has been secured from the city and county, or city or town, the commission may likewise order such physical connection, within such city and county, or city or town, between two (2) or more railroads which enter the limits of the same. The commission shall by order direct whether the expense of the connections referred to in this section shall be borne jointly or otherwise.
Idaho Code § 61-510