The Nilgiri Mountain Railway (NMR) is a railway in Nilgiris district, Tamil Nadu, India, built by the British in 1908. The railway is operated by the Southern Railway and is the only rack railway in India. The railway relies on its fleet of steam locomotives. NMR switched to diesel locomotives on the section between Coonoor and Udhagamandalam. Local people and visitors led a campaign to return to steam locomotives in this section. In July 2005, UNESCO added the Nilgiri Mountain Railway as an extension to the World Heritage Site of Darjeeling Himalayan Railway. The site then became known as Mountain Railways of India. History In 1854, plans were made to build a mountain railway from Mettupalayam to the Nilgiri Hills. However, it took the decision-makers 45 years to cut through the bureaucratic red tape and complete the construction. The line was completed and opened for traffic in June 1899. It was operated first by the Madras Railway under an agreement with the government. The Madras Railway Company continued to manage the railway line on behalf of the government for a long time until the South Indian Railway company purchased it. In 1907, the railway received four Double Fairlie locomotives to work the line. These were part of a batch built by the Avonside Engine Company in 1879 and 1880 for service in Afghanistan, but had been in store since 1887. The Fairlies continued in use until at least 1914. Initially, Coonoor was the final station on the line. In September 1908, the line was extended to Fernhill. By 15 October 1908, it was extended to Udagmandalam. These extensions from Coonoor on the same gauge over a distance of were done at a cost of 2,440,000. Operators The NMR and all of its assets, including the stations, the line, and the track vehicles, belong to the Government of India and are managed by the Ministry of Railways. The Southern Railway performs the day-to-day maintenance and management, but several programs, divisions and departments of the Indian Railways are responsible for operating, maintaining and repairing the NMR. Rack and pinion Between Mettupalayam and Coonoor, the line uses the Abt rack and pinion system to climb the steep gradient. The NMR is the only rack railway in India. Rolling stock NMR uses 'X' Class steam rack locomotives, most manufactured by the Swiss Locomotive and Machine Works of Winterthur in Switzerland, on the rack and