Kolkata Metro: The only Metro of IR. কলকাতা মেট্রো : তিলোত্তমার জীবন রেখা ।। - PPG

when u observe the wheel u can see the inner portion is a little bit down than the outer one.. that means the inner acts as a giude... now see the pic... the wheel is there and the track is set to go straight... so what happens is tat since the track is open, it can go straight..
Now when the track is switched, the open portion joins the track and the closed one in the figure opens up... So wat hapens as the diameter of the inner is greater than the outer, as the wheel reaches the switch, the wheel travels throu the switch to the new one

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