A rack railway is a type of railway that uses a toothed rack rail in addition to the regular rails. This design allows trains to climb steep gradients that would be difficult or impossible for conventional trains. The train's wheels engage with the rack, providing extra traction and stability on steep slopes. Rack railways are often found in mountainous regions, where they serve as a means of transportation to high-altitude destinations. Famous examples include the Gornergrat Railway in Switzerland and the Mount Washington Cog Railway in the United States. These railways are popular for both tourism and practical transport.