From the FGW▸ website :
06:00 Portsmouth Harbour to Cardiff Central due 09:41
This train has been started from Bristol Temple Meads at 09:14.It will no longer call at: Portsmouth Harbour, Portsmouth & Southsea, Fratton, Cosham, Fareham, Southampton Central, Romsey, Salisbury, Warminster, Dilton Marsh, Westbury, Trowbridge, Bradford-On-Avon, Avoncliff, Freshford, Bath Spa, Oldfield Park and Keynsham.This is due to a train fault.
I went for that this morning, only just managed to squeeze the Trowbridge passengers on the following service, a 150 from Weymouth, there were a few unhappy people at Bradford and Freshford who didn't get on.