In which railway section in India is this new indigenous metre gauge steam engine under test trials?

The Nilgiri Mountain Railway (NMR) is a 1,000 mm (3 ft 3+3⁄8 in) metre gauge railway in 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. Between Mettupalayam and Coonoor, the line uses the Abt rack and pinion system to climb the steep gradient. This railway section relies on its fleet of steam locomotives. The 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.

Indian Railways' Nilgiri Mountain Railway section stretches from the entire Mettupalayam – Udagamandalam (Ooty) in the Nilgiri Mountains. It has the steepest track in Asia with a maximum gradient of 8.33%. Indian Railways’ Golden Rock workshop which falls under the Southern Railway (SR) division has recently manufactured the first-ever coal-fired X Class Steam Locomotive in the country. The steam locomotive which was inaugurated on the 27th of August will be put to use in the UNESCO (The United Nations Educational, Scientific and Cultural Organization) World Heritage Site viz, Nilgiri Mountain Railway (NMR) after more test trial runs.