Definitions for "rail-trail"
a former railroad that has been converted to a trail for non-motorized recreational and transportation purposes such as hiking, biking, in-line skating, and cross-country skiing
an abandoned railbed used as a non-motorized public trail with transportation and recreation in mind
a recreational or non-motorized transportation path (sometimes called a greenway if you include the natural and/or landscaped buffers) which has been converted from an abandoned railroad corridor for public use