Section 164. Hours of labor on street railroads

No employee engaged in the
  operation of a street surface or elevated railroad  of  whatever  motive
  power  owned  or  operated  by a corporation whose main line or route of
  travel lies principally within a city of  the  first  or  second  class,
  shall  be  employed  more than ten consecutive hours, including one-half
  hour for dinner, in any  day,  except  that  in  cases  of  accident  or
  unavoidable delay extra work may be performed for extra compensation.