Whenever the construction of a new railway line is under consideration, preliminary investigations are done by the railway administration to determine how the proposed line will fit in with the general scheme of future railway development. The preliminary investigations are normally based on a careful study of the following:
(a) Existing topo sheets and other maps of the area
(b) Published figures of trade and population of the area to be served
(c) Statistical data of existing railway lines in similar terrain in other areas
As a result of these investigations, it becomes possible to decide whether or not the new railway line is required and surveys should then be undertaken to get more details of the new line being contemplated.