(b)alter the course of any rivers, brooks, streams or other water courses, for the purpose of constructing and maintaining tunnels, bridges, passages or other works over or under them and divert or alter either temporarily or permanently, the course of any rivers, brooks, streams or other water courses or any roads, streets or ways, or raise or sink the level thereof, in order to carry them more conveniently over or under or by the side of the railway;
