The electrification of the Valleys railway lines will be completed by 2019 according to the UK Transport Minister, Simon Burns MP.
The project's cost is an estimated 350 million pounds with work due to start in 2015.
During Transport Questions in the Commons the Minister said it would be "a significant boost" to South Wales, which "will create tremendous opportunities for business travel and passenger travel".
The scheme is part of a modernisation which includes the 1 billion pounds electrification of the line between Swansea and London.
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