Answer:

Why railways are not CONCENTRATED in mountainous desert and Central port of India

Explanation:

The Mountain railways of India are the railway lines that were BUILT in the mountains of India.

Three of them, the Darjeeling Himalayan Railway, the Nilgiri Mountain Railway, and the Kalka–Shimla Railway, are collectively designated as a UNESCO World Heritage Site under the name "Mountain Railways of India". The fourth railway, the Matheran Hill Railway, is on the tentative list of UNESCO World Heritage Sites. All FOUR are narrow-gauge railways, and the Nilgiri Mountain Railway is also the only rack railway in India.

Some mountain railways such as the Lumding–Badarpur section have been converted to 1,676 mm (5 ft 6 in) broad gauge, which is the nationwide standard, while some railways such as the Kangra Valley Railway are in the process of being converted to broad gauge. Some mountain railways, such as the Jammu–Baramulla line, are currently under construction, and others are in the planning stage, such as the Srinagar–Leh line, the Bilaspur–Leh line, the Jammu–Poonch line, and the Chota Char Dham Railway. All the mountain railways constructed in RECENT times use 1,676 mm (5 ft 6 in) broad gauge.