Why is this train so frequently cancelled. It is a popular commuter train from Swindon, or would be except that it is so frequently cancelled many passengers use the earlier (less convenient) train.
Does if form the start of the intermediate daytime service which provides the half hourly Cardiff - Paddington trains by adding to the hourly Swansea - Paddington service? It's my understanding that this extra service is regarded as something of an extra, and is the first to be withdrawn in the event of operational difficulties as all the withdrawal does is put people back 30 minutes.