The Severn, like other English rivers, may be said to have been the pioneer of railways along its banks: first, in having done much to correct the inequalities of the surface; secondly, in having indicated the direction in which the traffic flowed; so that early in the history of railway enterprise eminent engineers, like the late Robert Stephenson, saw the desirability of following its course, and thus meeting the wants of towns that had grown into importance upon its banks, wants which the river itself was unable to supply.