ยง  240.  Gates  or vestibule doors. Every car used for passengers upon
  elevated railroads shall have gates at the outer edge of  its  platforms
  so  constructed that they shall, when opened, be caught and held open by
  such catch or spring as will  prevent  their  swinging  and  obstructing
  passengers  in  their  egress from or ingress to such cars, or vestibule
  doors so constructed as to slide into the body of  the  car;  and  every
  such  gate  or door shall be kept closed while the car is in motion; and
  when the car has stopped and a gate or door has  been  opened,  the  car
  shall not start until such gate or door is again firmly closed.
Structure New York Laws
Article 6 - Rapid Transit Act of 1875
220 - Application for Railroad; Commissioners.
221 - Oath and Bond of Commissioners.
222 - First Meeting of Commissioners.
223 - Determination of Necessity of Railroad and Route.
224 - Adoption of Plans, and Terms Upon Which Road Shall Be Built.
225 - Appraisal of Damages and Deposit of Money as Security.
226 - Shall Prepare Certificate of Incorporation; Proviso as to Forfeiture.
228 - Commissioners to Deliver Certificate; Affidavit of Directors.
231 - Where Route Coincides With Another Route.
232 - Commissioners to Transfer Plans.
233 - Commissioners to File Report; Confirmation Thereof.
235 - Quorum; Term of Office; Removal; Vacancies in Board of Commissioners.
236 - Abandonment or Change of Route; New Commissioners; Their Powers and Proceedings.
237 - Abandonment of Portion of Route by Elevated Railroad.
238 - Increased Deposit, When and How Required.
239 - Trains to Come to Full Stop.
240 - Gates or Vestibule Doors.
241 - Penalty for Violation of Two Preceding Sections.
242 - Sections to Be Printed and Posted.
244 - Lighting Cars on Elevated Railroads in Cities of Over Twelve Hundred Thousand Inhabitants.