a scene at Wellington on the Nilgiri Mountain Railway, India, circa 1910

The NMR is a metre-gauge 46 km line in Tamil Nadu built by the British in 1908, now operated by the Southern Railway and is the only rack railway in India.

The railway has a fleet of steam locomotives but switched to diesel locomotives on the section between Coonoor and Udhagamandalam. Locals 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.