Ar yr 28ain o Chwefror, bu i archwiliadau diogelwch cyn dechrau'r gwasanaeth ddatgelu difrod i'r olwynion ar nifer o'n trenau pellter maith sy'n rhedeg o Orllewin Cymru i Manceinion, o Gaerdydd i Gaergybi ac o Gaergybi i Birmingham.  Nid oedd y difrod i'w weld mewn unrhyw fan arall ar reilffyrdd Prydain.
On 28 February, safety inspections prior to start of service revealed damage to the wheel sets on a number of our longer-distance trains which run from West Wales to Manchester, Cardiff to Holyhead and Holyhead to Birmingham. The damage seen had not been experienced anywhere on Britain’s railway.