On 1 Mar, 01:05, MIG wrote:
And a nightmarish interchange, presumably.

Not at all. It's a simple stairs-and-corridor link between the two
island platforms, and there are lifts too (step-free according to the
Tube map).

I must have misunderstood. I was interpreting the plan as reinstating
some kind of platforms on the main lines, which I thought were the
other side of a depot from the current stations.

There isn't a connection from the main lines to the existing stations
south of Watford or north of Chalk Farm.

At Queens Park, the lines are all close and parallel, although a
bridge is involved. There are un (barely?) used platforms on the main
lines already.

Indeed, I am quite curious as to why you believe the interchange would
be so nightmarish. A quick look at some satellite imagery shows it to
be quite matter of course (hopefully, this works!):
http://maps.google.co.uk/maps/ms?ie=...06738&t=h&z=18

The depot is quite some way to the east, and not too great a concern
to this proposal. Admittedly, the platforms already exist at Queens
park, but that shouldn't make too great a obstacle to reinstating the
platforms at Willesden should the benefits justified it.