The action for the recovery of taxes so paid under protest shall be brought in the superior court of the county wherein the tax was collected or, for actions solely against one county, in any superior court permitted under RCW
36.01.050, or in any federal court of competent jurisdiction: PROVIDED, That where the property against which the tax is levied consists of the operating property of a railroad company, telegraph company or other public service company whose operating property is located in more than one county and is assessed as a unit by any state board or state officer or officers, the complaining taxpayer may institute such action in the superior court of any one of the counties in which such tax is payable, or in any federal court of competent jurisdiction, and may join as parties defendant in said action all of the counties to which the tax or taxes levied upon such operating property were paid or are payable, and may recover in one action from each of the county defendants the amount of the tax, or any portion thereof, so paid under protest, and adjudged to have been unlawfully collected, together with interest thereon at the rate specified in RCW
84.69.100 from date of payment, and costs of suit.