A rail trail is a shared-use path on a railway right of way. Rail trails are typically constructed after a railway has been abandoned and the track has been removed but may also share the right of way with active railways, light rail, or streetcars (rails with trails), or with disused track. As shared-use paths, rail trails are primarily for non-motorized traffic including pedestrians, bicycles, horseback riders, skaters, and cross-country skiers, although snowmobiles and ATVs may be allowed. The characteristics of abandoned railways—gentle grades, well-engineered rights of way and structures (bridges and tunnels), and passage through historical areas—lend themselves to rail trails and account for their popularity. Many rail trails are long-distance trails, while some shorter rail trails are known as greenways or linear parks.