18.104.22.168.5 Addition of Car Top Railing
(c) when the railing is neither stowed nor in the fully extended position, the car shall not be permitted to operate.
(d) switches used to monitor the stowed position shall have contacts that are positively opened mechanically when the railing is moved from its stowed position.
(e) switches used to monitor the fully extended position shall have contacts that are positively opened mechanically when the railing is moved from its fully extended position.
(f) the occurrence of a single ground; or the failure of a contactor, a relay, or any single solid-state device; or a failure of a software system in the circuits incorporating these switches shall not permit operation other than as specified in (a), (b), or (c).
(g) means shall be provided to prevent upward movement of the car beyond the point required to maintain top-of-car clearances when the railing is not in the fully stowed position. Activation of the means shall not cause an average retardation exceeding 9.81 m/s2 (32.2 ft/s2).
(h) when in the fully extended position, the railing shall meet the requirements of 2.10.2 and shall be designed to prevent accidental disengagement.
(i) the force required to extend or retract the railing shall not exceed 220 N (50 lbf).