It could be a source of extra rolling stock for FGW▸ , I'd love to see the looks on people's faces when the 0657 from Taplow rolls in pulled by a steam engine!
(more seriously, do they have diesel locos that could be used elsewhere, and what is likely to happen to the stock now that they are no longer able to operate?)
I gave some semi-serious (but purely theoretic) thought to the use of some of the heritage stuff on current day (and day to day) services and conclude that it's a nice but impractical / expensive idea.
a) The old stuff is pretty worn out and will have huge maintenence issues to keep it going
b) The old stuff's likely to use more fuel and be less efficient
c) As each of the old stuff things is likely to be unique or one of few, there's a problem with exprertise
d) It may not be easy to get spares for the old stuff
e) There may not be specialists to operate the old stuff (and they are getting old)
f) Old stuff need more staff (like firemen and guards)
g) Old stuff may not meet modern safetly standards / may not mix well with very fast modern trains
h) Old stuff may be smelly and dirty and the ride may not be very comfortable
i) The old stuff may not be quick enough to get from Plymouth to London in less than 3 hours
j) There will be huge arguments over whether the old stuff looks good in the new
GWR▸ colours
Against those arguments, for certain holiday destination lines there's some potential sense in mixing heritage and national rail services, and attracting significant numbers of enthusiast could be economically sound - an
ATOC» report
http://www.atoc.org/clientfiles/files/publicationsdocuments/ConnectingCommunitiesReport_S10.pdf mentions some, and there was another report too I think. I could quite forsee Cardiff - Taunton becoming Cardiff - Minehead in alternate hours (1 extra train), Exmouth - Paignton becoming Exmouth - Kingswear, and a couple of others. But that's the reverse proposal - new stock on old line. Old stock on current line has been talekd about, but there are very real reliabiity fears, and fears the line(s) would become seasonal, and perhaps problmes as the years went by. Interesting to look at the Lymington experience with heritage "slammers" and consider the current discussion about the Isle of Wight ... also the Cardiff Bay Bubble Car (is the Aylesbury one still running?)