Nid yw’r seilwaith rheilffyrdd y tu allan i leiniau’r Cymoedd wedi’i ddatganoli i Gymru ac er mwyn mynd ati i wella’r leiniau lliniaru yn unol ag argymhelliad yr adroddiad, bydd angen i Lywodraeth y DU hithau chwarae ei rhan.
Rail infrastructure outside of the Core Valley Lines is not devolved to Wales and in order to deliver the major upgrade of the relief lines recommended by the report, the UK Government will need to play its part.