invitation for expression of interest for the purpose of empanelment of agencies for carryingout detailed engineering survey work including drone survey, lidar survey, reconnaissanceengineering survey, preliminary engineering survey, final location survey, soilinvestigations, land acquisition, preparation of gad, structural design and proof- check forproviding survey works of new lines, gauge conversion, doublings, road over bridges etc.and preparation of dpr / de on western railway construction organization.bidding type normal tender .