Roedd dwy elfen benodol ynghlwm wrth y gwerthusiad ac ystyriwyd ailagor Llinell Glynebwy ym mis Chwefror 2008 rhwng Parcffordd Glynebwy a Chaerdydd Canolog, a hefyd ddarparu cerbydau ychwanegol er mwyn darparu gwell gwasanaethau ar adegau prysur ar y llinellau canlynol: o Ferthyr Tudful i Aberdâr, Pen-y-bont ar Ogwr i Ynys y Barri, Treherbert i Gaerdydd Canolog a Rhymni i Gaerdydd Canolog.
The evaluation consisted of two distinct strands and considered both the new services on the reopened Ebbw Vale Line in February 2008 between Ebbw Vale Parkway and Cardiff Central, and the provision of additional rolling stock to provide strengthened services at peak times on the; Merthyr Tydfil to Aberdare, Bridgend to  Barry Island, Treherbert to Cardiff Central and Rhymney to  Cardiff Central lines.