Section 208-E. Extra work by members of certain police forces

Notwithstanding the provisions of any general, special or local  law  or
  any  rule or regulation of any police department or commissioner or head
  thereof, any member of a  police  force  of  a  transit  authority  with
  facilities  in  any  municipality  may  engage in extra work for another
  employer outside his regular hours of  duty  for  not  exceeding  twenty
  hours  a  week  provided  that  such  extra  work  does not interfere or
  conflict with his regular duties as a member of the police force of such
  a transit authority or his availability for emergency  duty  nor  affect
  his  physical  condition  to  the  extent that it impairs his ability to
  efficiently perform such duties and further provided that  the  type  of
  employment shall first be approved by the appropriate transit authority.