SDCL § 49-16A-102: Railroad police--Appointment and employment by railroad.

A railroad organized under the laws of this state, or doing business within this state, may, at its own expense, appoint and employ policemen at stations or other places on its roads within this state for the protection of its property and the preservation of order on its premises, and in and about its cars, depots, depot grounds, yards, buildings, or other structures.