<Tr> <Td_colspan="2"> (edit on Wikidata) </Td> </Tr> <P> The Mountain railways of India refer to the railway lines built in the mountains of India . </P> <P> Three of these railways, Darjeeling Himalayan Railway, Nilgiri Mountain Railway, and Kalka--Shimla Railway have been collectively designated as a UNESCO World Heritage Site, also named as "Mountain Railways of India", while the fourth railway, Matheran Hill Railway is in tentative list of UNESCO World Heritage Site . These all are narrow - gauge railways . The Nilgiri Mountain Railway is also, the only rack railway in India . </P> <P> Some railways are under construction like Jammu--Baramulla line . Few railways are proposed to be built in future, such as Bilaspur--Mandi--Leh line, Jammu--Poonch line, Srinagar--Kargil--Leh line and Chota Char Dham Railway . Mountain railways constructed in recent times all use 1,676 mm (5 ft 6 in) broad gauge . </P>

Three mountain railway lines in india which has been designated as unesco world heritage site