This site includes three railways. The Darjeeling Himalayan Railway was the first, and is still the most outstanding, example of a hill passenger railway. Opened in 1881, its design applies bold and ingenious engineering solutions to the problem of establishing an effective rail link across a mountainous terrain of great beauty. The construction of the Nilgiri Mountain Railway, a 46-km long metre-gauge single-track railway in Tamil Nadu State was first proposed in 1854, but due to the difficulty of the mountainous location the work only started in 1891 and was completed in 1908. This railway, scaling an elevation of 326 m to 2,203 m, represented the latest technology of the time. The Kalka Shimla Railway, a 96-km long, single track working rail link built in the mid-19th century to provide a service to the highland town of Shimla is emblematic of the technical and material efforts to disenclave mountain populations through the railway. All three railways are still fully operational.