A funicular railway is a type of transportation system that uses a cable-driven mechanism to move cars up and down steep slopes. It typically consists of two cars that are connected by a cable, allowing one car to ascend while the other descends. This design helps balance the weight and reduces the energy needed for operation. Funicular railways are often found in hilly or mountainous areas, providing access to scenic viewpoints or tourist attractions. They are popular in cities like Lisbon and San Francisco, where steep terrain makes traditional rail systems impractical.