Okla. Stat. tit. 66, § 66-306: Essential governmental functions

The Legislature hereby finds and declares that the exercise of

the powers granted by the Railroad Revitalization Act is in all

respects for the benefit of the people of the state, to enhance

their safety at public railroad crossings, for the increase of their

commerce and prosperity, and for the improvement of their health and

living conditions, and as such the acquisition, construction,

reconstruction, repair, replacement, operation and maintenance of

railroad rights-of-way and trackage projects by the Department

constitute the performance of essential discretionary governmental

functions as set forth in Section 155 of Title 51 of the Oklahoma

Statutes.