Nothing in this section shall be construed to relieve a railroad or the operator of a locomotive from any duty or responsibility on the part of it or him to give warnings by means of a bell or by any other device which is not herein specifically prohibited. It is unlawful for the operator of a locomotive within the limits of Baltimore City to sound a horn or whistle attached to a locomotive when approaching a street grade-crossing, except on main line track movements of the Baltimore and Ohio Railroad Company between Camden Station, Mt. Clare yard and the southerly and southwesterly City limits. Any person violating the provisions of this section shall be deemed guilty of a misdemeanor and upon conviction thereof, subject to a fine of not to exceed $10 for each such offense. City Code, 1966, art. 20, §24 1976/83, art. 20, §17 Ord. 60-415