After disputes running since 2012, the Welsh and British governments have agreed a funding deal to upgrade railways in South Wales.

The British government will provide £230 million, which will cover the cost of electrifying the Great Western Main Line to Swansea, and partially fund the electrification of the Valley lines. The Welsh government will provide the remaining £170 million, which it hopes to recoup through ticket sales.

Journeys from both Merthyr Tydfil and Treherbert to Cardiff will take less than 50 minutes once the work is completed.

Prime Minister David Cameron welcomed the agreement, as did Welsh First Minister Carwyn Jones, who described the upgrades as “a very important project”.

Work on the improvements is expected to start in 2019. This will come after the railways devolve to the Welsh government in 2018, following the end of Arriva Wales’ franchise. The Welsh government will then be able to choose the subsequent rail operator.