 as a peace officer by a law enforcement agency; (0)  a railroad peace officer appointed by the director under Article 0.000, Code of Criminal Procedure, who holds a certificate of authority issued by the director under that article and a peace officer license issued by the Texas Commission on Law Enforcement; or (0)  a special ranger of the Texas and Southwestern Cattle Raisers Association appointed by the director under Article 0.000, Code of Criminal Procedure, who holds a certificate of authority issued by the director under that article and a peace officer license issued by the Texas Commission on Law Enforcement