2016 New York Laws
RRD - Railroad
Article 3 - (Railroad) CONSTRUCTION, OPERATION AND MANAGEMENT
51 - Weight of rail.

  51.  Weight  of  rail.  The  rail  used  in the construction or the
  relaying of the track of every railroad hereafter  built  or  relaid  in
  whole  or  in  part  shall  be  of iron or steel, weighing not less than
  twenty-five pounds to the lineal yard on narrow-gauge roads, and on  all
  other  roads not less than fifty-six pounds to the lineal yard on grades
  of one hundred and ten feet to the mile or  under,  and  not  less  than
  seventy  pounds to the lineal yard on grades of over one hundred and ten
  feet to the mile, except for turnouts, sidings and switches.