Saturday, 8 February 2014

Evolution of AC Double Deckers

Double Decker coaches were first introduced on Indian Railways in 1975 mainly aimed at providing higher carrying capacity in short distance commuter trains.  The intended objective of Indian Railways was achieved but these Non-Air Conditioned coaches could not become very popular among commuters.  The main reason was that they had to face lot of dust ingress from the low level windows of the lower deck and the view outside was also not very pleasant at the platform level height.  With these concerns, proliferations of Non-AC double deckers on Indian Railways was not pursued further.
            With past experience at hand, Indian Railways once again conceived double deckers but this time in Air Conditioned configuration that could address the problems faced in Non-AC variants and the first announcement for introduction of AC Double Deckers was made by the Minister of Railways in the Rail Budget 2009.

  Considering the existing fixed structures like Road-over-bridges, Foot-over-bridges, electrical traction equipment etc. across the entire length and breadth of Railways, it was a real challenge to design a double decker coach without raising the overall height.  This challenge was further compounded by the fact that air-conditioning equipment and air-ducts are also to be provided within the same envelope.
   Taking it as a mission, a team of design engineers of Indian Railways started the development process of putting more coach per coach and that too, totally in-house.  Their ingenuity was proved when Rail Coach Factory, Kapurthala a production unit of Indian Railways, was ready with the first prototype AC Double Decker in a record time of only nine months.  After all mandatory tests in the field, the first AC double decker train was introduced on Indian Railways between Howrah and Dhanbad in October 2011.
Now further, an improved design of such train has been developed and its services between Jaipur and Delhi and Ahmedabad and Mumbai have been introduced. Such services are also planned between Habibganj-Indore and Chennai-Bangalore in near future. AC double decker train with improved passenger friendly design is having capacity of 120 passengers per coachcompared to 78 passengers in Shatabdi Chair cars thus increasing the capacity by more than 50 per cent.  The AC double decker train, with low fares, has brought the comfort of AC travel within the bounds of many wannabe passengers and is becoming popular among passengers.
The new air-conditioned coaches have many technical features like light weight stainless steel body with aesthetically pleasing interiors.  Eurofima design bogies with air springs provide superior ride quality.  For safety of the passengers, couplers with anti-climbing features and shells with crashworthy structure have been introduced.  This design was substantially lower tare weight per passenger, thus making them highly energy efficient.

The overall height of these coaches is only marginally higher (4.5 inches) because the space for two decks has been managed by optimally using the well area between the two wheeled bogies.  Latest design software was used in the development process and it was extensively validated through virtual prototyping before taking up actual manufacturing.
The successful development of AC Double Decker Coach is a clear illustration of Indian Railways’ prowess in development of technology and its resolve to meet the expectations of an aspiring nation.

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