- Route
- Mettupalayam – Coonoor – Udagamandalam (Ooty)
- State
- Tamil Nadu
- Year started
- 1908 – completed to Udagamandalam
- UNESCO status
- UNESCO World Heritage Site since 2005 – part of the Mountain Railways of India
The Nilgiri Mountain Railway is one of India's most distinctive heritage railway experiences. The metre-gauge railway connects Mettupalayam with Udagamandalam, popularly known as Ooty, through the Nilgiri Hills of Tamil Nadu.
Construction was especially challenging because the railway climbs from approximately 326 metres above sea level to more than 2,200 metres.
Its most remarkable feature is its rack-and-pinion traction system, used on steep sections of the route. A toothed rack installed between the rails helps locomotives safely climb gradients that would be difficult for a normal adhesion railway.
Construction began in the nineteenth century and the railway was completed to Ooty in 1908.
UNESCO added the Nilgiri Mountain Railway to the Mountain Railways of India World Heritage property in 2005, recognising both its engineering importance and exceptional level of historic preservation.