If train cross any station in high speed, chain pull will not work (to overcome this, traveler break air pipe, which is quite risky for bth traveler & train--which may derail)..DD do hav PSR & chain pull works easily!!
IR Staff too ease chain pull..like there exist Salempur Jn where Godan/LTT-CPR Exp dnt stop!! Nw in every run, the starter read red & go green till train enter station premise..& the moment it starts chugging, chain get pulled!! If it would hav green, high speed pass-thru wouldnt hav let chain-pull work!!