Hyderabad, Aug 27 : Hyderabad Metro Rail Limited (HMRL) has commenced a drone survey in the old city of Hyderabad for expansion of the metro rail network. HMRL commenced a drone survey of metro rail alignment and properties likely to be affected after Telangana Chief Minister K. Chandrasekhar Rao's direction to speed up metro rail preparatory works in the old city. Apart from the conventional survey, drone survey is also commenced to take exact measurements of the affected properties which are required for road widening in the narrow stretch between Darul-shifa junction and Shalibanda junction and for construction of metro stations, HMRL Managing Director N.V.S. Reddy said on Sunday. He said that the protection of about 103 religious and other sensitive structures including 21 masjids, 12 temples, 12 ashoor khanas, 33 dargas, seven graveyards and six chillas is a major challenge for the metro construction. The drone survey will be helpful in evolving appropriate engineering solutions to save religious and other sensitive structures. Metro alignment and pillar locations are being planned in such a way that there is no adverse effect on these religious and other sensitive structures, Reddy added. He further said that the drone survey enables quick collection of real time data, high resolution imaginary, 3D modeling, seamless integration of GIS (Geographic Information System) data and CAD software, data analysis and visualization. Simultaneously, tenders are also being finalised for starting soil investigation in the coming few days, Reddy said, adding that the soil investigation will start from Falaknuma end where Falaknuma metro station will be located. Apart from MGBS which is already an existing station, the 5.5 km metro stretch in the old city will have 4 other stations namely, Salarjung Museum, Charminar (metro stations will be about 500 metres away from these two monuments), Shalibanda and Falaknuma. /IANS