The cost of providing a realistic TransWilts service on the Westbury to Swindon section next year is quoted to me (and to others) as 1 million pounds.  I've not been given a breakdown of that figure, so I can't tell you why it's much higher than the figure or 600k that I've calculated as follows:

150k - Hire of train and servicing
250k - Crew
100k - Station and rail access charges
50k - Publicity and Marketing
50k - Admin and organisation

You'll notice that my figure is for an improved service of 8 trains per day, with two full-shift crews 7 days per week and a dedicated class 153 train.  Current costs will be lower.

Where does the 1 million come from?  Well - I guess you could come up with a price of 1 million pounds if you add on a 400k profit margin for the operator ... but I rather suspect that it's based on a calculation similar to mine that's been conveniently rounded to the nearest million.