Charles Ellson wrote:
On Sun, 21 Jun 2015 02:41:35 +0100, Basil Jet
wrote:

On 2015\06\20 22:03, Recliner wrote:
Roland Perry wrote:
In message , at 17:31:34 on Sat, 20 Jun 2015,
" remarked:
I wonder if they employ trippers on that stretch or if they fit the
test trains with AWS.

http://www.bbc.co.uk/news/uk-england-29110845

I've seen the tube trains under test at Old Dalby (last time I drove up
to the East Midlands a month ago). Unfortunately there wasn't anywhere
convenient for me to stop to take a photo.

The other odd thing about the line is the OHL a long way from any
electrified service lines. https://goo.gl/maps/Q70Uo

I think it's the only section of track, anywhere, with both fourth rail and
overhead electrification. I think that it's currently being used for both S
stock and IEP testing. Old Dalby is also where the currently surplus S7
stick waiting to enter service is being stored.

One unusual location for ex-LU stock the BBC missed is Long Marston:
http://www.railtechnologymagazine.co...e-this-anymore

IIRC Drayton Park has both fourth rail and overhead,
although obviously not for much distance.

The fourth rail might not be doing a lot unless it has been left
connected but dropped onto the sleepers as done between Harrow and
Watford.

It's certainly not a functional fourth rail, and nor would 313s connect to
a centre rail anyway.

Basil Jet wrote:
On 2015\06\21 02:45, Recliner wrote:
Basil Jet wrote:

IIRC Drayton Park has both fourth rail and overhead,
although obviously not for much distance.

The fourth rail isn't operational. It was disconnected when the overhead
was installed. It does have a short length of third rail and overhead, but
that's not uncommon.

This seems to imply that overhead + 4th rail is in some way harder to do
than overhead + 3rd rail... I would have thought it would be the other way around.

I think it just so happens that no fourth rail DC trains normally share
tracks with any overhead line AC trains.

On 2015\06\21 03:01, Recliner wrote:
Charles Ellson wrote:
On Sun, 21 Jun 2015 02:41:35 +0100, Basil Jet
wrote:
IIRC Drayton Park has both fourth rail and overhead,
although obviously not for much distance.

The fourth rail might not be doing a lot unless it has been left
connected but dropped onto the sleepers as done between Harrow and
Watford.

It's certainly not a functional fourth rail, and nor would 313s connect to
a centre rail anyway.

So why aren't all of the water pipes near the GN&C corroding merrily,
which is the problem 4th rail was invented to solve?

Basil Jet wrote:
On 2015\06\21 03:01, Recliner wrote:
Charles Ellson wrote:
On Sun, 21 Jun 2015 02:41:35 +0100, Basil Jet
wrote:
IIRC Drayton Park has both fourth rail and overhead,
although obviously not for much distance.

The fourth rail might not be doing a lot unless it has been left
connected but dropped onto the sleepers as done between Harrow and
Watford.

It's certainly not a functional fourth rail, and nor would 313s connect to
a centre rail anyway.

So why aren't all of the water pipes near the GN&C corroding merrily,
which is the problem 4th rail was invented to solve?

There's plenty of third rail track in tunnels around the world and, indeed,
in London. Just think of the ELL.

On Sun, 21 Jun 2015 02:04:13 +0000 (UTC), Recliner
wrote:

Basil Jet wrote:
On 2015\06\21 02:45, Recliner wrote:
Basil Jet wrote:

IIRC Drayton Park has both fourth rail and overhead,
although obviously not for much distance.

The fourth rail isn't operational. It was disconnected when the overhead
was installed. It does have a short length of third rail and overhead, but
that's not uncommon.

This seems to imply that overhead + 4th rail is in some way harder to do
than overhead + 3rd rail... I would have thought it would be the other way around.

c.313s don't use the fourth rail so it is redundant.

I think it just so happens that no fourth rail DC trains normally share
tracks with any overhead line AC trains.

Not since the DC line was converted to 3rd rail.

On Sun, 21 Jun 2015 02:07:28 +0000 (UTC), Recliner
wrote:

Basil Jet wrote:
On 2015\06\21 03:01, Recliner wrote:
Charles Ellson wrote:
On Sun, 21 Jun 2015 02:41:35 +0100, Basil Jet
wrote:
IIRC Drayton Park has both fourth rail and overhead,
although obviously not for much distance.

The fourth rail might not be doing a lot unless it has been left
connected but dropped onto the sleepers as done between Harrow and
Watford.

It's certainly not a functional fourth rail, and nor would 313s connect to
a centre rail anyway.

So why aren't all of the water pipes near the GN&C corroding merrily,
which is the problem 4th rail was invented to solve?

Probably nothing more than a lack of leakage current. If the tunnels
are fairly dry and the traction bonds are in good condition then the
leakage will be minimal. Many of the water pipes "upstairs" will now
be plastic or interrupted by plastic sections which will further limit
the flow of leakage currents through them; they're only going to
corrode "merrily" when you have a combination of water and metal
touching a different metal or other conducting material. On various LU
lines, the only reason for 4-rail electrification is for
standardisation.

There's plenty of third rail track in tunnels around the world and, indeed,
in London. Just think of the ELL.

wrote:
On Sat, 20 Jun 2015 21:03:03 +0000 (UTC), Recliner
wrote:

Roland Perry wrote:
In message , at 17:31:34 on Sat, 20 Jun 2015,
" remarked:
I wonder if they employ trippers on that stretch or if they fit the
test trains with AWS.

http://www.bbc.co.uk/news/uk-england-29110845

I've seen the tube trains under test at Old Dalby (last time I drove up
to the East Midlands a month ago). Unfortunately there wasn't anywhere
convenient for me to stop to take a photo.

The other odd thing about the line is the OHL a long way from any
electrified service lines. https://goo.gl/maps/Q70Uo

Swindon works had a short length of third rail at one time within a
caged compound, not long enough to run but for powering up some
Southern EMU's that were being worked on.

I think it's the only section of track, anywhere, with both fourth rail and
overhead electrification. I think that it's currently being used for both S
stock and IEP testing.

Anywhere is a big place, The Milan Metro whose line 1 is electrified
with a fourth rail almost like the LU ones has its track shared by
overhead powered trains which came later for other routes.
Both systems are DC so it is much simpler than the UK AC -DC Mix.

ICBW but wasn't one of the continental test tracks given a fourth rail
to test some tube stock? But it could have been on a circuit with no
overhead.

Which stock would that be? The only tube trains built outside the UK for a
very long time would be the extra Jubilee line 1996 stock, but I don't know
if that was put on an Italian test track. With such a small order (four
train sets and 59 trailer cars), I doubt that it was worth equipping an
Italian track with a fourth rail electrification system.

http://www.alstom.com/press-centre/2...ound-20030619/

Recliner wrote:

I think it's the only section of track, anywhere, with both fourth rail and
overhead electrification. I think that it's currently being used for both S
stock and IEP testing. Old Dalby is also where the currently surplus S7
stick waiting to enter service is being stored.

How about this then:

http://www.bbc.co.uk/programmes/b00llg30

Bombardier test track at Derby.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

Chris J Dixon wrote:
Recliner wrote:

I think it's the only section of track, anywhere, with both fourth rail and
overhead electrification. I think that it's currently being used for both S
stock and IEP testing. Old Dalby is also where the currently surplus S7
stick waiting to enter service is being stored.

How about this then:

http://www.bbc.co.uk/programmes/b00llg30

Bombardier test track at Derby.

Yes, you're right, I'd forgotten that one. Incidentally, that link doesn't
take me to it, but I found this YouTube video:
http://youtu.be/oYoHGSdcQpE

In message
-septembe
r.org, at 21:03:03 on Sat, 20 Jun 2015, Recliner
remarked:
I've seen the tube trains under test at Old Dalby (last time I drove up
to the East Midlands a month ago). Unfortunately there wasn't anywhere
convenient for me to stop to take a photo.

The other odd thing about the line is the OHL a long way from any
electrified service lines. https://goo.gl/maps/Q70Uo

I think it's the only section of track, anywhere, with both fourth rail and
overhead electrification.

Might they perhaps have some short stretches at the factory in Derby
too?
--
Roland Perry