In message , at 12:44:51
on Tue, 14 Jun 2016, David Cantrell remarked:
But I wonder why you cite Croydon, which does have TfL
services, rather than Bromley and Bexley, which don't?
Just to be pedantic: Bromley has TfL London Overground services from
3 stations in the borough.

Apart from the old East London line, isn't the Overground charged as if
it were a National Rail service?

No, it has special fares, even lower then underground ones.
--
Roland Perry