Dave Arquati wrote:

The reason for longitudinal seating is to provide more space for standing passengers.

If they make use of it, but I tend to find that passengers only stand
one abreadth regardless of the seating layout. Meanwhile, when you are
sitting, you don't have the inconvenience of having people stand right
over you.

In addition, transverse seating provides more seating space.

An interchange between the NLL and Northern line at Hampstead would be
so incredibly expensive it would be completely unfeasible - both the NLL
and Northern line are in deep tunnel at quite differing levels, and the
construction of an interchange station would therefore require extremely
difficult and complex tunnelling. The demand (which would chiefly be to
and from just six stations north of Hampstead) is very unlikely to
justify such costs.

Maybe. Most of those stations are moderately close to either the
"Thameslink" (now capital connect) or the Jubilee and can make the
change at West Hampstead for the stations west of Hampstead, while for
the stations eastward you make the Camden Town / Camden Road
interchange (which is about 4 minutes because I've made it).

It does mean if you wish to go West you are back-tracking on yourself,
i.e. you go from Hampstead towards Camden Town then back towards
Hampstead again. Or you make a longer walk. There is the option of
using buses to make part of the link.

The best hope for a Northern line interchange is Primrose Hill; if/when
Queen's Park to Stratford services start running, then they will pass
through disused platforms about 200m from Chalk Farm station. This would
still provide for flows to/from stations east of Camden, and would
cost a fraction of the price (especially if the old station structures,
which seem to be in situ, can be revived).

Other more-possible-than-Hampstead possibilities are Tufnell Park, and
even Camden Town to Camden Road (an additional exit from the northern
ends of the platforms at Camden Town to a second ticket office closer to
Camden Road was floated as a potential congestion-relief measure).

Archway and Upper Holloway are already not that far apart.

I'm pretty sure cycles will still be permitted outside the peak hours,
as is standard practice on all above-ground and subsurface sections of
the Underground.

At the moment on Silverlink they're allowed at any time (as far as I'm
aware) which is useful for commuting to work if you want to cycle at
either end (often quite necessary) but don't wish to cycle the whole
journey (possibly too long). Now if they really want to promote bike
use and they're going to make the trains more frequent how about
either:

1. A proper cycle area on the train (with no seats at all)
and / or
2. Allow cycles on alternate trains with such a facility.