On Sat, 27 Oct 2012 01:52:33 +0100, wrote:

On Fri, 26 Oct 2012 17:22:33 -0500, (Mark Brader) wrote:

Mark Brader:

the Valtellina line near Lake Como in September 1902; and that
technical details of the system and an illustration of a Valtellina
line locomotive can be found in "History of the Electric Locomotive"
(1969) by F.J.G. Haut.

Looking around on the Web for photos showing such a locomotive,
I only find this one, although it's on several web pages:

http://en.wikipedia.org/wiki/File:Ka...an_mozdony.jpg

So I suspect it's the same one as in Haut's book. Anyway, the
interesting thing is the collector that contacts the overhead wires,

Also note how high the arm is above the locomotive. You'd never
fit that thing into a Metropolitan or District tunnel. They must
have had a different sort of collector in mind.

Bonnet mounted collectors have been used on some electric locos where
there were limited clearances.
http://www.flickr.com/photos/45127721@N05/6581147453
is an example on a UK industrial system that survived till the late
1980's.
In a tunnel setting arcing from such a low collector in the drivers
view can cause disruption to vision and I shouldn't think it would do
much for the health of the eyes either.

That can be avoided by using the rear collector if two are fitted as
on the Italian locomotives in :-
http://en.wikipedia.org/wiki/Three-p...lectrification

On the subject of Italy, I hadn't realised they were still using
3-phase into the 1970s :-
http://www.photorail.com/phr1-leFS/e432.htm
(with an interesting effect caused by smoke/steam/fumes coming from a
"chimney" at one end)

Trolley poles would be another possibility. Used in the original
Cascades tunnel electrification in the United States which was a 3
phase system.

Distance memory's of trolley buses and dewirements suggest they would
be impractical on a system with many junctions like the Metropolitan
even though a railed vehicle would have less tendency to pull the
booms offline.

G.Harman