N.Y. Comp. Codes R. & Regs. tit. 12, § 8-1.39 – General.

(a) In future installations, guide rails for both car and counterweight of all elevators shall be of steel.
Exceptions:
Wood guide rails shall be permitted where none of the following conditions are exceeded: (1) Passenger elevators with a capacity not exceeding 2,000 pounds. (2) Freight elevators with a capacity not exceeding 5,000 pounds. (3) Elevators with a rise not exceeding 75 feet. (4) Elevators with a speed not exceeding 100 feet per minute.
(b) Cast iron shall not be used for guide rails.
(c) Steel guide rails and posts for maple guide rails shall be securely fastened with iron or steel brackets or their equivalent, of such strength, design and spacing that the guide rails shall not reflect more than one-fourth inch under normal operation; they shall withstand the application of the safety when stopping a fully loaded car or the counterweight. The guiding surface of the guide rails for elevators requiring safeties shall be finished smooth and joints shall be tongued and grooved or dowelled.
(d) The guide rails shall extend to the level of or above the overhead beams and shall rest on suitable supports. (See section 8-1.53 for table of weights and sizes.)