The joining of the two IETs▸ at Swindon wasn?t planned.
The first train from Gloucester (already cut back from Cheltenham due to late running earlier) was cancelled at Swindon due to a lack of a driver to take it forward. So the following service from Swansea was coupled to it on platform 3.
There was also another incident at the station today. A Swansea service from Paddington booked to go via Gloucester was routed into platform 4 - but you can?t gain the Kemble line from there. After a 45 minute delay it was reversed out, crossed over and continued its journey.
Hope that was a computer error, rather than a human error, as a member of the Swindon panel society, that is pretty much rule one, you cant go to Gloucster from the down main...