49 CFR §207.2

1. (a)Railroad police officer means a peace officer who is commissioned in his or her state of legal residence or state of primary employment and directly employed by or contracted by a railroad to enforce state laws for the protection of railroad property, personnel, passengers, and/or cargo.
2. (b)Commissioned means that a state official has certified or otherwise designated a railroad employee as qualified under the licensing requirements of that state to act as a railroad police officer in that state.
3. (c)Property means rights-of-way, easements, appurtenant property, equipment, cargo, facilities, and buildings and other structures owned, leased, operated, maintained, or transported by a railroad.