"Jonathan Morton" wrote in message
...
"Dave Rowsell" wrote in message
...
In the 1950's I lived in North Harrow and think the Met had only two
tracks
running between Harrow on the Hill and Moor Park and beyond. A recent
photo
shows a second set of lines on the south west side of the station.

That could of course have been the BR (ex-GCR) lines. South of and
including
Harrow-on-the-Hill they are on the south-western side of the formation,
giving Harrow three island platforms (from south to north Marylebone
down/up, Met down and Met up). I can't remember whether this arrangement
continues north of Harrow Junction.

Clive's UndergrounD Guides web pages say "Traffic on the Metropolitan
was
heavy enough that it was quadrupled from Finchley Road to Kilburn in
1913,
Wembley Park in 1915, Harrow in 1932, Northwood Hills in 1961, and
Croxleyhall Junction (north of Moor Park) in 1962." I am right in
understanding this to mean that the second pair of lines were built in
1961.

Does any one have information on this second set and/or any images of
their
construction.

Sorry, no images, but the dates would be right, co-inciding roughly with
the
intoduction of the A59 and A60 stock (IIRC, "A" for Amersham and the years
'59 and '60). Not sure if the reference to "second pair" of lines is
strictly correct. Certainly the Met south of Harrow is paired by direction
(very efficient use of space, with the slows in the middle, because you
can
use a single island platform where there are no fast platforms, as at
Northwick Park for instance, and one island for each direction where fast
trains stop, Harrow for instance). I think this continues north of Harrow,
but I can't remember exactly. So I would guess that quadrupling was
achieved
by a new track on each side, BICBW.

P. E. Garbutt's "How the Underground Works" (London Transport, 1968
revision) has track plans of the completed Harrow - Moor Park 4-tracking
(fig 18), and of the staging of the works 1959-1962 (fig 19). In essence,
new double track was built to the west of the line from N. Harrow to
Northwood Hills (inc), with the existing platforms remaining on the new slow
lines and no platforms on the fast; at Northwood the new tracks are to the
east, with a new southbound platform & the site of the old southbound
platform becoming the northbound one, the old northbound being demolished;
at Moor Park the new lines were back on the western side, with the site of
the old southbound platform becoming an island serving the slow lines. and a
new island platform for the fast lines.

Hope this makes sense!

Mike