"Mizter T" wrote in message
oups.com...

Oyster card season tickets are already accepted on the railway across
London. Oyster Pre-Pay is a much more complex product designed for a
fully gated system and TfL fare structures. As the rail system is
different in this respect there are significant issues to overcome to
ensure that passengers don't get overcharged and to minimise the
opportunity for fare evasion. One example is the high cost of
installing gates or Oyster card readers at stations. There are also
issues around the compatibility of Oyster with the alternative smart
card standard called ITSO (see: http://www.itso.org.uk/about.asp). The
various issues will take some time to sort out - TfL planned Oyster for
4 years before the cards were made public.

There is a good article by Roger Ford, in his "Informed Sources" column of
the new (August) edition of "Modern Railways" for those who are interested.
Basically, the conundrum is whether to go with the existing
non-ITSO-compliant Oyster when the APTIS machines are replaced in 2006
(APTIS can currently cope with Oyster due to some clever coding that took
advantage of spare capacity within the machines) or whether to wait and go
with a fully ITSO-compliant system. It also points out that of the three
current replacement systems for APTIS (Tribute, Shere Smart and Fujitsu
Star) *none* of these currently have Oyster capability!