(1) There shall be a minimum of 2 opposing guide rails extending to a point 152.4 mm (6 in.) beyond the full height of travel of the car when the counterweight buffer is fully compressed.

(2) All rails shall be attached by bolts, lag screws or other approved methods to a vertical supporting member which shall not exceed 12.7 mm (0.5 in.) deflection with the application of a 250 lb. horizontal thrust at any point.

(3) Wood guide rails shall be at least 38.1 mm (1.5 in.) x 38.1 mm (1.5 in.) vertical grain fir or equivalent and shall not vary more than 4.7752 mm (0.188 in.) in thickness on the sides which the brakes contact. All joints shall be kept smooth and even.