Except as provided in subsection (b) of this section, it is unlawful for any railroad company or other person to place or cause to be placed any railroad car of any description on any turnout or private switch in any manner that obstructs free passage along the line of a street or alley. This section does not apply to the extent that the placement is authorized by and complies with:a rule, regulation, or directive of the Director of Transportation; or a contract approved by the Board of Estimates and entered into by the railroad company or other person and the Mayor and City Council of Baltimore. City Code, 1879, art. 40, §5 1893, art. 41, §5 1927, art. 39, §5 1950, art. 29, §4 1966, art. 20, §4 1976/83, art. 20, §4 Rev. Ords. 1858-034 Ord. 48-482 Ord. 05-056