On October 2, 1968, the US Congress passed the “National Trails Act.” Then on January 1, 1976, the Railroad Revitalization and Regulatory Reform Act under which the “Rails to Trails” program was inaugurated. From there the Rails to Trails Conservancy, a not for profit organization, was founded and has actively worked to transform over 9000 miles of abandoned railroad right-of-way to trails which the public can use for both commuter transportation and recreation. Today, there are more than 1,600 preserved pathways that form the backbone of a growing trail system that spans communities, regions, states and, indeed, the entire country. (http://www.railstotrails.org/aboutUs/index.html)
In my own state, Massachusetts, I regularly use the Minuteman Bikeway, an 11 mile route which extends from Cambridge to Bedford via Arlington and Lexington. There is also a 2nd spur, not part of the Minuteman, which extends from Cambridge to Somerville, approximately 2 miles. Both these paths are heavily used. During the winter months Cambridge, Arlington, Lexington and Bedford plow the path following snowstorms. The Cambridge to Arlington portion is particularly heavily used by commuters who take the subway to its end in Cambridge and then walk the route to their homes in Arlington. This trail is over 20 years old and its heavy use to testament to the vision the Rails to Trails Conservancy has.
The building of such a trail requires a local and state commitment to construct such a path on an abandoned railroad right-of-way. Although there is a funding requirement from the state, the federal government provides the majority of the funding under the Rail Revitalization Act. To be certain, this is a very simplified version of what must be done however I point to it as being eminently doable with a reasonable level of backing from state and local authorities.
To my dismay, Massachusetts has not done very much with its hundreds of miles of available rail lines while other states, Ohio, Indiana, and Michigan, to name a few, are very actively extending their system of paths. The value of these paths is obvious to even the casual observer. I write the recommending that any who read this actively support the building of new trails in their own states. The following link will take you to the Rail to Trails Conservancy.