D7666 wrote:
Now that TfL is going to take over Silverlink Metro presumably train
replacement becomes their repsonsibility also ?

As mentioned in another thread, 313s are 30 years old so no that far
off replacement. ISTR there is already a determined quantity of cars
from the Bombardier Movia catalogue for A60 and other surface stock.
313 age falls between C69 and D78, so with 2012 Olympics at Stratford
might it be possible they will want to rid NLL (thats the NLL line
itself of 313s - before D78 goes - and more surface gauge Movias are
the answer ?

Great minds, etc (or fools):
http://groups.google.co.uk/group/uk....91c152e8214678

I assume there are no major difficulties in producing an AC/DC Movia -
if not, then this could be a good idea. It would also make sense to run
Movias on the ELL, rather than using the blatantly inappropriate
Junipers - that way TfL has an entirely common fleet.

If (big if this) TfL decided to re-extend Bakerloo trains to Watford
over their newly gained empire, by using more BCV tube stock cars in
an add-on batch, would the possibility of being able to use tube size
stock from Watford Junction over the proposed Croxley link have
significant civil engineering cost savings by constructing to the
smaller tube guage? Might tip the balance towards making this project
go ahead ?

I don't get this - it would involve replacing a sizeable % of the core
Metropolitan Line service into Baker Street with tube-guage stock,
which isn't kind to pax and which is frowned upon for safety reasons. I
don't even see any savings: AFAIK none of the Croxley link is in
tunnel, and the track width is the same for tube and subsurface stock.

BTW, I thought Bakerloo-taking-over-DC-lines thing was pretty much a
done deal, rather than a big if?

I won't mention the impact of Movia three phase motors on the existing
NLL DC power supply ... oops ...

Oh, go on... is this a serious issue? Would it mean a Southern Region
style gazillion pound power upgrade?

(uk.t.l added)

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

John B wrote:


D7666 wrote:
As mentioned in another thread, 313s

Great minds, etc (or fools):
http://groups.google.co.uk/group/uk....91c152e8214678


Not at all.

That *IS* the other thread !!!


--
Nick

John B wrote:

I don't get this - it would involve replacing a sizeable % of the core
Metropolitan Line service into Baker Street with tube-guage stock,

I was referring to Bakerloo not Metropolitan.

BTW, I thought Bakerloo-taking-over-DC-lines thing was pretty much a
done deal, rather than a big if?

Perhaps I have mis read other discussions but I thought I had
understood it was what forums were suggesting rather than whats
happening.



I won't mention the impact of Movia three phase motors on the existing
NLL DC power supply ... oops ...

Oh, go on... is this a serious issue? Would it mean a Southern Region
style gazillion pound power upgrade?

I thought I'd throw it into the fire to see what happened.

The problem will be the same - you are replacing DC motors with
asynchronous AC motors so there will be the same higher average
current and higher I-squared-R heating problem but lower starting peak
current. To what extent LU is already capable of dealing with this ...
over to the traction engineers.

--
Nick

"D7666" wrote in message
oups.com
John B wrote:

I won't mention the impact of Movia three phase motors on the
existing NLL DC power supply ... oops ...

Oh, go on... is this a serious issue? Would it mean a Southern Region
style gazillion pound power upgrade?

I thought I'd throw it into the fire to see what happened.

The problem will be the same - you are replacing DC motors with
asynchronous AC motors so there will be the same higher average
current and higher I-squared-R heating problem but lower starting peak
current. To what extent LU is already capable of dealing with this ...
over to the traction engineers.

What sort of traction do other recent Tube stock builds have (ie, 1995/6
and 1992 stocks)? In particular, the 1992 stock has very dramatic
acceleration, while the A60s are extremely leisurely.

Nigel Pendse wrote:

What sort of traction do other recent Tube stock builds have (ie, 1995/6
and 1992 stocks)? In particular, the 1992 stock has very dramatic
acceleration, while the A60s are extremely leisurely.

C line DC motor with DC chopper [92 stock]
J line AC motor with GTO [96 stock]
N line AC motor with IGBT [95 stock]

95 stock being newer than 96 stock has IGBT gubbins instead of GTO.

All other tube lines and all surface lines are camshaft / contactor /
DC motors (apart from odd experiments all of which I think have
ceased).

So a rough analogy is 92 stock is like main line 317/319/321
generation, 95/96 like Electrostars and Desiros, and the rest are like
Mk.1s. (I said *rough* - cue pedants to list all anomalies exceptions
corrections and omissions.)

--
Nick