Extension of work across or under highway or railroad; duty as to construction and maintenance; cost. The drainage work may be extended across or under any highway and may also be carried under or through any railroad or tramway. The authority which maintains the highway through which the conduit crosses shall construct and maintain the same in good condition and repair, free from obstruction, at its own expense. The owner of the railroad or tramway under or through which the conduit is to be constructed shall construct and maintain the same in good condition and repair, free from obstruction, at its own expense

ORS 549.360 — under Chapter 549.