Connecting Mettupalayan to Ooty is the 46 km long Nilgiri Mountain Railway. It runs on 1000 mm gauge railway. The first section which went up to Coonoor was completed in 1899 by the Nilgiri Railway Company. It was later extended to Ooty in 1903.
This distinctive rail system is the steepest one in the whole of Asia. The slopes are accompanied by the numerous curves. To ensure a smooth ride, the Nilgiri Railway uses a unique ‘rack and pinion’ rail system. Interestingly, while ascending up the hills the engine pushes the train from behind and while descending, the engine is in the front. The rack system is used on the route to Mettupalayam Coonoor because of the continuous gradient.
At present all traffic on the rack section is effectively handled by the eight X class locomotives built by SLM of Switzerland. These locomotives have four cylinders. While the main cylinders use high-pressure steam to drive the wheels of the loco, the small cylinders use low-pressure steam to drive the rack system of the Nilgiri Railway System. It is interesting to note that the youngest X class loco is over 50 years old and the oldest is 80 years old.
The rack system and the complicated locomotives are equally unique. There are four brakes on the Nilgiri locomotives. While two hand brakes are used for shunting the other two are used for descending the steep gradients. The brake system on Nilgiri locomotives is as complicated as it was in 1886. The train journey back then took 17 hours.
The present scenario:
The present scenario has changed with the rapid advancement of modern infrastructures. The journey from Ootacamund to Mettupalaiyam takes about 10 hours. The Nilgiri Railway is the triumph of the engineering unit in the east.
The railway line is metre gauge. It is leveled till Kallar after which the rack rails appears. The line rises to 4,363 feet in the next twelve miles to Coonoor.
The construction incurred heavy expense because the tunnels had to be properly built. In addition a big bridge had to be constructed over the river Bhawani along with 26 other small bridges.