The other flaw in the main arguments are a "through service", a
"through service" to what exactly? Camden? Change. Bank? Change.
Euston? Change.

The current through service is to Morden or Kennington.

The notion of reducing train lengths incidentally to save costs is
ridiculous in this instance because there would have to be customised
rolling stock for a branch line.

No, there wouldn't. The Northern Line trains are 3-car units, coupled
in pairs to make 6-car trains. You could run a single unit as the
shuttle.

Except the trains are formed with UNDMs at the inner ends of the units
and therefore have no driving cabs (Apart from the shunting panel, of
course). 95 stock doesn't have any double ended 3 car units.
--
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