Va. Code § 56-353
The president or any other executive officer of any railroad company incorporated by this Commonwealth may, with the approval of the circuit court of any county or the corporation court of any city through which the road passes or has its chief office, appoint one or more police agents, who shall have authority in all cases in which the rights of such railroad company are involved to exercise within the Commonwealth all powers which can be lawfully exercised by any police officer for the preservation of the peace, the arrest of offenders and disorderly persons, and for the enforcement of laws against crimes; and such president or other executive officer may remove any such agent at his pleasure; but, any court giving such consent may at any time revoke it.
Va. Code § 56-353