Having made a number of enquiries I wasn't expecting any special trains at 
Castle Cary.   Well, maybe not strictly true; I was expecting things like 
extra stop.   Then last Thursday I came across a poster at Bath Spa advising 
that certain S Wales services (among others) would be cancelled to provide 
stock to Glastonbury services.   Even so, I was only expecting FGW stock. 
I had a search around FGW and National Rail sites just to confirm my 
impression and couldn't find any reference to even the services that would 
be operated by the S Wales stock.   Then, this morning I looked at the live 
departures for CLC on National Rail and it was only showing the normal 
service, nothing extra at all and that seems to have been the case all day.

Despite that, I visited the station this morning (the variety of buses can 
also be quite interesting; this year there are 3 Routemasters (at least)). 
As I approached I was surprised to see one of the Virgin liveried 67 hauled 
sets about to depart.

So, what should I have done to find out what specials would be operated? 
Where else should I have looked?