A cog railway is a type of railway that uses a cogwheel system to climb steep slopes. This system includes a central cog rail that engages with a cogwheel on the train, allowing it to ascend or descend steep gradients safely. Cog railways are often found in mountainous regions, providing access to scenic views and remote areas. One famous example of a cog railway is the Cog Railway to Mount Washington in New Hampshire, which is the highest peak in the northeastern United States. These railways are popular for both tourism and transportation, offering a unique experience for passengers.