Jarle H Knudsen wrote:
If, when visiting London as a tourist in August, I should like to ride one
of the underground lines in its entirety, which line and branch would you
suggest, and why?

--
jhk

I'd suggest the District Line from Ealing Common to Upminster. That way
you see a variety of architectural styles, ranging from the Art Deco of
Ealing through the Victorian splendour of Earl's Court and St. James'
Park, with a variety of styles all along the route. Passing through
some fairly stunning modernisations, such as Westminster and Gloucester
Road, with lots of old unmodernised charm still around, like Barons'
Court and South Kensington, and a fair mixture of cut-and-cover tunnel
(between Earl's Court and Mile End), but open running at each end
beyond those. Also, some interesting parallel running with other lines
between Turnham Green and Baron's Court (Piccadilly Line), Circle Line
(on same tracks) in central section, and Hammersmith & City Line at the
Eastern end. If lucky, you will also be able to see the Metropolitan
Line as you travel between Tower Hill and Aldgate (i.e. Aldgate
Station) Central Line at Mile End and Jubilee Line at West Ham.

On the maintenance side, you will see Ealing Common Depot and the
remnant of the vast Acton Works past Acton Town, and get a glimpse of
Lillie Bridge Depot West of West Kensington, Triangle Sidings at
Gloucester Road and the huge Upmister Depot East of Upminster Station.

Similarly, the Hammersmith & City Line between Hammersmith and Barking
has large sections either on or over ground (on viaducts at the Western
end), with lots to see. I'd suggest that most of the stations are
older, and some rather shabby, but the highlights would certainly be
the parallel runnning with the mainline at Paddington and near Barking
(also of course on the District Line), and some interesting
interchanges at Baker Street, Farringdon and Mile End

Although they also have much to recommend them, huge parts (and all of
the Victoria Line) of the Bakerloo, Jubilee, Northern, Piccadilly and
Central Lines are in tunnel, and therefore not much can be seen, except
the stations themselves.

I hope you enjoy your visit and good luck!

Marc.