Locomotives of India~
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Nilgiri Mountain Railway (NMR) is a 46 Km long 1000 mm gauge railway connecting
Mettupalayam (1069 ft) to Ooty (7228 ft). Its first section upto Coonoor was
completed in 1899 by the Nilgiri Railway Company and was extended to Ooty in
1903. In those days it served as a popular getaway from the sweltering heat
of the plains for the British in India. Even today it is a popular hill resort
attracting hoards of tourists.
rail system is unique - it is the steepest one in Asia ( the steepest gradient
is about 1in12). In combination with this gradient there are curves as sharp
as 18 degrees! To overcome this incline it uses a unique ABT(Alternate Biting
System) commonly known as `rack and pinion' rail system and curiously the name
of the inventor is also Michael Abt! In this system, between the two conventional
rails, there are two rack bars, out of step with each other, on which the pinions
of the locos & coaches 'climb' in a similar manner as a person climbing
a ladder using his feet alternately.
convention of the engine leading the train on level lines, here the engine
is pushing the train from behind when ascending and is in front stopping it
from running amuck when going downhill. The main incline between Mettupalayam
to Coonoor is a continuous gradient where the rack system is used. After Coonoor
until Ooty the gradient is relatively eased (this section is now worked by
YDM4 diesel locos).
have been the motive power here since the inception of the line in 1899. Presently
all traffic on the rack section is in the able hands of eight X class
locomotives built by SLM of Switzerland.These are compound locomotives having
four cylinders instead of the conventional two. The main cylinders use high-pressure
steam and drive the wheels of the loco whereas the smaller cylinders using
low-pressure steam drive the rack system. The youngest X class loco is over
50 years old and the oldest is 80 years old against the average of 25 years
working life of a steam loco.
yard with Nilgiris as a backdrop.
is the only operative rack rail system in Asia.
of an X Class.
a viaduct in the midst
of thick forest.