John Rowland wrote:

I'm interested that they will be running a longer line, yet there
aren't any new trains. Are they reducing peak service between Arnos
and Cockfosters, or west of Rayners?

The direct line to T5 and back adds very little extra distance compared
to the T4 loop. If they need an extra train or two, Tube Lines should be
able to supply that from the existing fleet. They told me some years
ago that this was the intention.

Also, if the press release is right about the service being faster, then
the time saved on the existing journey would help to compensate for the
extra distance and dwell time for the extension to T5.
--
Richard J.
(to e-mail me, swap uk and yon in address)