Briefly describe the Portage Railroad:

A portage railway is a short and possibly isolated section of railway used to bypass a section of unnavigable river or between two water bodies which are not directly connected. Cargo from waterborne vessels is unloaded, loaded onto conventional railroad rolling stock, carried to the other end of the railway, where it is unloaded and loaded onto a second waterborne vessel. A portage railway is the opposite of a train ferry.