Mae Llywodraeth Cymru wedi bod yn cydweithio'n glos â Llywodraeth y DU dros y ddwy flynedd ddiwethaf ar y rhaglen gymhleth o gytundebau sy'n gweddnewid y ffordd y mae gwasanaethau rheilffyrdd yn cael eu darparu yng Nghymru. Daeth un rhan o'r gwaith hwnnw i ben llynedd pan drosglwyddwyd awdurdod y fasnachfraint i Weinidogion Cymru a chytuno ar y trefniadau ariannu. Ers hynny, mae llawer iawn o waith wedi'i wneud ar drosglwyddo asedau Llinellau Craidd y Cymoedd (CVL) er mwyn i Lywodraeth Cymru allu rheoli'r gwasanaethau a'r buddsoddiad mewn seilwaith.
The Welsh Government has been working closely with the UK Government over the last two years on the complex programme of agreements that are changing the delivery of rail services in Wales. Last year part of this work drew to a close with the transfer of franchising authority to the Welsh Ministers and the agreement on the funding arrangements. Since then there has been a considerable amount of work undertaken to progress the transfer of the Core Valleys Lines (CVL) rail asset so that both infrastructure investment and services can be controlled by the Welsh Government.