As smaller, shorter branches of major railways became unfeasible to maintain economically, rail companies consolidated their lines and the short branch lines became obsolete and abandoned. In an effort to use those lines for something useful and beneficial, the rail trail became common in the United States and other countries. Also known as a linear park, a rail trail is any trail or pathway that was built on a railway easement that is no longer in use. They are generally multi-use trails and cater to walkers, cyclists, rollerbladers, and other recreationalists, usually excluding motorized traffic.
A rail trail usually spans several miles in a straight line — hence the designation linear park — because railways were designed to cross terrain at easy inclines and with few sharp turns; therefore, trails that follow these old railways mimic those characteristics. Another name for a rail trail is a greenway, since many of these parks cut through wooded areas. It is not uncommon to find a rail trail that runs through historic areas, and many of these trails tout the history of the surroundings as one of its key features. The first rail trail to open in the United States was the Elroy-Sparta State Trail in Wisconsin, which opened in 1965. Since then, the Rails-to-Trails Conservancy, a non-profit group based in Washington, D.C. has worked to convert hundreds of miles of abandoned railway lines into trails for hiking and other outdoor activities.
A rail trail can vary in length from only a mile or less, to well over a hundred miles (161 km). The longest rail trail in the United States is the Katy Trail in Missouri, which spans 225 miles (362 km). The nature and length of the trail depends on a variety of issues, the most prominent of which is land rights and the ability to effectively convert the railways into trails. Many communities oppose rail trails because of increased traffic, decreased security, and other unforeseen issues.
Further, because railways were often built on a combination of privately owned land, federal land, and easements — or special rights to use lands owned by another entity without that entity's explicit permission — it can be difficult to get permission to convert railways to trails. Some of the agreements and deeds for these lands were written several decades and even centuries ago, further complicating the issue and making property boundaries difficult to pinpoint.