Oregon Revised Statutes Revenue and Taxation § 308.550

(1) When a company owns, leases, operates over or uses rail, wire, pipe or pole lines, operational routes or property within and without this state, if the department values the entire property within and without this state as a unit, it may ascertain the property subject to taxation in Oregon by the proportion which the number of miles of rail, wire, pipe or pole lines or operational routes in Oregon, controlled or used by the company, as owner, lessee, or otherwise, bears to the entire mileage of rail, wire, pipe or pole lines or operational routes controlled or used by the company, as owner, lessee, or otherwise.

(2) If the value of any property having a situs in this state, of a company operating both within and without the state, cannot fairly be determined in the manner prescribed in subsection (1) of this section, the Department of Revenue may use any other reasonable method to determine the proper proportion of the entire property assessable for taxation in this state.

(3) The assessed value of the property of a water transportation company apportioned or allocated to Oregon shall not reflect so much of the value of its watercraft as is fairly attributable to voyages made by such watercraft exclusively on the high seas or between inland water ports or termini and the high seas. Voyages made to Oregon ports for the sole purpose or purposes of picking up or discharging company personnel, making repairs, refitting, or taking on supplies shall not be used for allocation or apportionment purposes.