On 20 Apr, 15:55, Mr Thant
wrote:
On 20 Apr, 15:40, Alistair Bell wrote:
it's clear that the shortest rail-only route to
Vauxhall is on the direct train to Clapham Junction. ...

I don't think you can do that - it's the shortest route to a London
Terminal (ie the nearest one), with allowances for journeys through
London Bridge etc. Otherwise - as you mention - it starts getting
silly. Not that this is codified anywhere.

If it's not documented anywhere, then my opinion is the opposite. In
the absence of a documented restriction, the passenger can choose
which station to travel to within a group by a permitted route, and
doubling back is often specifically allowed:
"GROUP STATIONS
The stations listed at the bottom of this page are grouped together to
improve interchange between trains by offering customers access to a
wider choice of train services and station facilities. A customer may
travel via any station in a group, including doubling back, provided
that the group is on one of the permitted routes between their origin
and destination stations. This extended availability is for
interchange purposes only and does not apply where the origin or
destination stations are part of a group."
(http://www.atoc.org/rsp/_downloads/R...ctions.htm#how
%20to%20determine)