The TransWilts may now be a unique line in the South West (
FGW▸ territory) in having a passenger service, but one which is so sparse that it's impractical for most people to travel along the route to actually make use of it, and when it does run the timings are hardly ideal.
There are a number of optimistic signs - such as the
GWRUS▸ - around at the moment, including a suggestion to take a "low cost option" which would provide a couple of extra round trips a day, plus a third extra northbound service. It looks to me as if extra - and
practical - journey opportunities it would provide would be quite out of proportion (in a positive way) to the very modest changes needed.
I've looked at this on the "TransWilts" board from an operational viewpoint - now I've produced some diagrams from the passenger (and want-to-be passenger) viewpoint:
http://www.wellho.net/mouth/2457_Railway-Arithmetic.htmlDoes my logic look correct to you? Almost a "too good to be true" yield on this on

.