The history of trade routes including rail lines and highways begins with the history of short-cuts in river trade. Portage is the practice of carrying boats across land as a safer, quicker way of cutting the corner made by a river bend. Over time, tracks made by portage practices themselves become known as portages. Portage is a verb-to-noun form.
On their return journey, the explorers met Indians who described a shorter route to Lake Michigan. The explorers taking the route, traveled up the Illinois River to the Des Plaines River. Canoeing up the Des Plaines they came to a place approximately midway between present day Summit and Riverside, Illinois. Here, at what is now known as the Chicago Portage, in September of 1673, they came to a little creek (Portage Creek the outlet of Mud Lake) which took them into and across Mud Lake to its eastern edge (the continental divide). At this point they carried – or portaged – their canoes across one and one half miles of open prairie to the west fork of the south branch of the Chicago River. The Chicago River led Marquette and Jolliet to Lake Michigan and back to Green Bay.
In the history of the idea of portage we find a precedent for the desire line made by walking feet finding social shortcuts across planned landscapes.
See the Tactic of the Shortcut