This *must* have been discussed here before, but I've done some
searching on Google Groups and can't find the answer. Why doesn't TfL
sell a one day travelcard on Oyster, to be used by those who need to
travel on National Rail? It seems any of the arguments involving poor
Oyster facilities on NR would also apply to period travelcards. The only
thing I can think of is that it might confuse customers who can't figure
out the difference with capping.
--
Michael Hoffman