For the acquiring of rights-of-way and property necessary for the construction of terminal railroads and structures, including railroad crossings, wharves, piers, docks, quays, grain elevators, cotton compresses, warehouses, and other riparian and littoral terminals and structures and approaches thereto needful for the convenient use of rights-of-way and property, the port authority may acquire the rights-of-way and property by purchase, by negotiation or by condemnation.