DEVELOPMENT :
The origins of WAG-12 can be traced back to a railway project approval in 2006, but no progress was made in the months that followed.In June 2008, the Ministry of Railways invited bids from global firms to design and develop the locomotives. The initial deal was to set up a new electric locomotive factory at Madhepura, Bihar to build and maintain 660 high-horsepower locomotives in a joint venture where Indian Railways would hold a 26% stake and the bidder 74%. This would have been the first foreign direct investment in the fully state-owned railway sector of the country. This invitation received bids from General Electric, Alstom, Bombardier, Siemens, China CNR, and CSR Corporation Limited. The number of locomotives to...
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be built was also increased from 660 to 800. The Research Design and Standards Organisation published a specification in June 2013, detailing the capability requirements for an eight-axle locomotive intended to be used on Eastern Dedicated Freight Corridor (EDFC). It was not until November 2015, however, that Alstom was finally awarded the contract to build the locomotives.[15]
The eight-axle design of the locomotive reportedly improves performance and minimizes energy consumption and maintenance costs. The locomotive incorporates special features based on the Alstom Prima T8 for operations in humid or dusty environments and extreme temperatures ranging from −50 °C (−58 °F) to 50 °C (122 °F). The cabin of the locomotive is comparatively larger and offers better comfort for drivers, especially during long-distance operations. The locomotives can also be equipped with climate control systems such as air conditioners, food preparation and storage facilities, and even a toilet—a standard that Indian Railways introduced in 2016

PRODUCTION :
As development of the engines progressed, Alstom outsourced the task of producing traction transformers for the locomotives to Swedish-Swiss multinational corporation ABB Group in 2016. As part of the Make in India initiative, these all-weather transformers were to be produced in Vadodara, Gujarat.In 2017, Alstom outsourced the task of developing, testing, and maintaining the brakes of the locomotives to German brake manufacturing firm Knorr-Bremse. Also a part of the Make in India initiative, these brakes were to be produced at Palwal in the Indian state of Haryana.The couplers of the locomotive were designed and developed by French Railway company Faiveley Transport. Around 85-90% of the components will be procured from within India.The first body shell of the locomotive was...
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delivered to the Haldia Port in West Bengal on 20 September 2017. It was then transferred to the Electric Locomotive Factory (Alstom Madhepura) for final assembly,which began on 11 October 2017.The first locomotive, numbered 60001, was tested in the Madhepura factory on 27 February 2018, one day before its initial launch date.
Deliveries of the locomotives are planned from 2018 through 2028, with the first locomotive slated to enter service in 2018, and a total of five by 2019. This is to be followed by the assembly of 35 new locomotives in 2020, 60 in 2021, and 100 locomotives each year from 2022 until all 800 locomotives are delivered.
Source : Wikipedia