I understand there were also signalling problems around the Bristol area this evening as well. Certainly a few late evening services running under caution through Bath Spa eastwards.
You probably know this train better than I do, as I no longer use these services to the extent I did in 2008 - 2010. But back then when I used to use this service or the earlier 18:00 from Bath Spa, by the time the train reached Weston-Super-Mare. I was often the only passenger in the 2.5 Carriages of First Class. Most other passengers who got off at Taunton boarded after WSM.
My personal view and thoughts to this train would be to put a Special Stop Order in at Westbury to allow passengers to change there for the 19:19 to Bristol Temple Meads. It would also have allowed them a service to Oldfield Park and Keynsham.
That being said, Westbury around this time was rather congested. I was sat between the
WSB» Station and Fairwood Junction on that very 19:19 train for around 5 minutes. The opposite track contained a Class 59 Loco which was shortly followed by an
HST▸ (The timing was right that it was probably your train from Chippenham John) and very quickly followed by a Voyager which was sitting in Platform 1. So it's possible that stopping the 17:30 from
PAD» at Westbury would have made the delays worse, but might have been better for some of the passengers.
I guess though that with a Paddington - Bristol Temple Meads train 30 minutes behind, that meant sending your train Fast to Taunton via Melksham purely to get it out of the way may have been controls thinking. Thus rendering my suggestion fairly less sensible unless you wanted Trowbridge or Warminster etc.
I could imagine that
BRI» was also rather congested/full platforms with westbound services. They may not have had anywhere to 'park' your train and the others behind it, thus diverting meant no hogging a platform needed for say a Cardiff Central service to reverse. Not to mention the few Voyagers and other units probably sat around occupying platforms doing nothing already.
Agreed definitely that your suggestion in hindsight is a good one, I'm just wondering with a Signalling issue (assuming it did exist) coupled with possibly limited platforms at BRI, whether that was the reasoning. I'm no expert so couldn't say for definite...
Again, my thoughts to all involved.