Building line national highway

Sir have 19 gunthe land at Pathargaon, 3 kms ahead of Karla, Lonavala. I would like to construct house on my plot. I would like to know how much distance should be left vacant from centre of National highway 4 (old highway). do I need to take permission from Highway Authority for constructing House. I head that earliest Building Line was 75 Meter from Centre of NH4 but now it is reduced to 50 metre from Centre of NH. Also what is rule for Railway Line. I mean to say how much distance should be left from Railway track for construction of house on your plot.