On 19 Apr, 16:36, "John Rowland"
wrote:

Tom Anderson wrote:

I think Peter thought, as i did, that this meant converting the power
supply to AC. Possibly by somehow stringing up cables in the tunnels.
Which does sound like it could take a while.

... but was planned for the Victoria Line a few years ago.

Really? When was this, how close did it come to happening, etc?

On 21 Apr, 09:04, Mizter T wrote:
I think Peter thought, as i did, that this meant converting the power
supply to AC. Possibly by somehow stringing up cables in the tunnels.
Which does sound like it could take a while.

... but was planned for the Victoria Line a few years ago.

Really? When was this, how close did it come to happening, etc?

About five years ago, and not very.

http://www.coroflot.com/public/indiv...dual_id=115892

--
John Band
john at johnband dot org
www.johnband.org

Change the traction package on a unit, and put it back in service.
Don't see why that would require closing the line. It might not
be possible to couple a DC unit and an AC unit in a single train,
but they can certainly share the same track and power rails.

If they do it lets hope they don't reduce the performance of the
central line trains to the slug like performance of the northern line
ones. The central trains are the only ones on the tube that have
anything approaching the decent acceleration that you'd expect on a
modern metro.

B2003

At 03:06:46 on Mon, 21 Apr 2008 Boltar opined:-


Change the traction package on a unit, and put it back in service.
Don't see why that would require closing the line. It might not
be possible to couple a DC unit and an AC unit in a single train,
but they can certainly share the same track and power rails.

If they do it lets hope they don't reduce the performance of the
central line trains to the slug like performance of the northern line
ones. The central trains are the only ones on the tube that have
anything approaching the decent acceleration that you'd expect on a
modern metro.

Is that because of the trains or because on the tube sections
acceleration is aided by gravity?
--
Thoss

"thoss" wrote in message
...
At 03:06:46 on Mon, 21 Apr 2008 Boltar opined:-


Change the traction package on a unit, and put it back in service.
Don't see why that would require closing the line. It might not
be possible to couple a DC unit and an AC unit in a single train,
but they can certainly share the same track and power rails.

If they do it lets hope they don't reduce the performance of the
central line trains to the slug like performance of the northern line
ones. The central trains are the only ones on the tube that have
anything approaching the decent acceleration that you'd expect on a
modern metro.

Is that because of the trains or because on the tube sections
acceleration is aided by gravity?

It is because the Central line has full automatic train operation (ATO),
which for normal day to day use drives the trains nearer the limits than
manual driving can. There is no reason why a change from DC to AC traction
would make performance worse, in fact it ought to improve AFAICT.

Paul S

Paul Scott wrote:
It is because the Central line has full automatic train operation (ATO),
which for normal day to day use drives the trains nearer the limits than

It can't be just that surely. Even on the long open stretches outside
where the drivers could give it some welly the northern trains still
chug along at a leisurely pace and take their time getting to it.
Perhaps the whole line has a low linespeed now, dunno.

B2003

On 21 Apr, 11:39, "Paul Scott" wrote:

"thoss" wrote:

At 03:06:46 on Mon, 21 Apr 2008 Boltar opined:-

Change the traction package on a unit, and put it back in service.
Don't see why that would require closing the line. It might not
be possible to couple a DC unit and an AC unit in a single train,
but they can certainly share the same track and power rails.

If they do it lets hope they don't reduce the performance of the
central line trains to the slug like performance of the northern line
ones. The central trains are the only ones on the tube that have
anything approaching the decent acceleration that you'd expect on a
modern metro.

Is that because of the trains or because on the tube sections
acceleration is aided by gravity?

It is because the Central line has full automatic train operation (ATO),
which for normal day to day use drives the trains nearer the limits than
manual driving can. There is no reason why a change from DC to AC traction
would make performance worse, in fact it ought to improve AFAICT.


Indeed - it's all about the ATO.

On Apr 21, 12:46*pm, Mizter T wrote:
On 21 Apr, 11:39, "Paul Scott" wrote:



"thoss" wrote:

At 03:06:46 on Mon, 21 Apr 2008 Boltar opined:-

Change the traction package on a unit, and put it back in service.
Don't see why that would require closing the line. * It might not
be possible to couple a DC unit and an AC unit in a single train,
but they can certainly share the same track and power rails.

If they do it lets hope they don't reduce the performance of the
central line trains to the slug like performance of the northern line
ones. The central trains are the only ones on the tube that have
anything approaching the decent acceleration that you'd expect on a
modern metro.

Is that because of the trains or because on the tube sections
acceleration is aided by gravity?

It is because the Central line has full automatic train operation (ATO),
which for normal day to day use drives the trains nearer the limits than
manual driving can. *There is no reason why a change from DC to AC traction
would make performance worse, in fact it ought to improve AFAICT.

Indeed - it's all about the ATO.

There is also the fact that all axles are motored on the Central
line's 1992 stock, whilst the Northern line's 1995 stock has two
trailer cars per 6 car unit. This means that the '92 stock is lighter
(per car). Having every axle motored generally allows better
acceleration, if all other things are equal. It will be interesting to
see how the Northern stock performs, once the trains are used to their
full potential.

On 21 Apr, 13:55, Andy wrote:

On Apr 21, 12:46 pm, Mizter T wrote:

On 21 Apr, 11:39, "Paul Scott" wrote:

"thoss" wrote:

At 03:06:46 on Mon, 21 Apr 2008 Boltar opined:-

Change the traction package on a unit, and put it back in service.
Don't see why that would require closing the line. It might not
be possible to couple a DC unit and an AC unit in a single train,
but they can certainly share the same track and power rails.

If they do it lets hope they don't reduce the performance of the
central line trains to the slug like performance of the northern line
ones. The central trains are the only ones on the tube that have
anything approaching the decent acceleration that you'd expect on
a modern metro.

Is that because of the trains or because on the tube sections
acceleration is aided by gravity?

It is because the Central line has full automatic train operation (ATO),
which for normal day to day use drives the trains nearer the limits than
manual driving can. There is no reason why a change from DC to AC
traction would make performance worse, in fact it ought to improve
AFAICT.

Indeed - it's all about the ATO.

There is also the fact that all axles are motored on the Central
line's 1992 stock, whilst the Northern line's 1995 stock has two
trailer cars per 6 car unit. This means that the '92 stock is lighter
(per car). Having every axle motored generally allows better
acceleration, if all other things are equal. It will be interesting to
see how the Northern stock performs, once the trains are used to their
full potential.


Though, speaking from a position of total ignorance here, might the
motors on the Northern line trains be more powerful, thus less are
needed?

Peter Smyth wrote:
It sounds like an April Fools joke but apparently TfL are considering
it.
http://tinyurl.com/5augle

Presumably if this were to go ahead the line would have to be closed for
an extended period.

"Range: between 90 000 000 and 130 000 000 GBP."

'Ow much?!?!?!
--
http://www.railforums.co.uk