Crossing London tube tracks
 

On 07/04/2008 10:32, MIG wrote:

I'm sure I remember Peter Purves going into the Underground with a
maintenance team for Blue Peter in the 1970s, and being shown a bank
of twelve light bulbs "just in case".

yes I remember that too, presumably 4 parallel sets of 3 lamps in series
so the -240/+410 gives each lamp about 250V?

Crossing London tube tracks
 

On Apr 7, 9:43 pm, Andy Burns wrote:
On 07/04/2008 10:32, MIG wrote:

I'm sure I remember Peter Purves going into the Underground with a
maintenance team for Blue Peter in the 1970s, and being shown a bank
of twelve light bulbs "just in case".

yes I remember that too, presumably 4 parallel sets of 3 lamps in series
so the -240/+410 gives each lamp about 250V?

Current Rail Indicator Devices. Fixed CRIDs are now being installed
on the headwall of many tube stations (small box with lights
indicating 'On', 'Off', 'Failed').

Crossing London tube tracks
 

On 07/04/2008 22:05, wrote:

Current Rail Indicator Devices. Fixed CRIDs are now being installed
on the headwall of many tube stations (small box with lights
indicating 'On', 'Off', 'Failed').

thanks, that led me to this
http://www.tubelines.com/news/releas.../20071008.aspx

Crossing London tube tracks
 

On Mon, 7 Apr 2008 02:32:13 -0700 (PDT), MIG
wrote:

On 7 Apr, 08:34, Stimpy wrote:
On Sun, 6 Apr 2008 21:18:22 +0100, Matthew Geier wrote



*Some one who regularly works on railway power systems may actually have
in their kit a 'test lamp' for 750v supplies.

IIRC, it's a bank of lamps "just in case" one or two lamps have blown

I'm sure I remember Peter Purves going into the Underground with a
maintenance team for Blue Peter in the 1970s, and being shown a bank
of twelve light bulbs "just in case".

(I also remember his reference to "the hiss of opening doors", despite
there being no such thing till the D78 stock [or since?]. In those
days the doors all opened silently and popped before closing.)

They all hiss when the seals are worn (and the door motors aren't
electric).

Crossing London tube tracks
 

In article ,
(Charles Ellson) wrote:

On Mon, 7 Apr 2008 02:32:13 -0700 (PDT), MIG
wrote:

On 7 Apr, 08:34, Stimpy wrote:
On Sun, 6 Apr 2008 21:18:22 +0100, Matthew Geier wrote

*Some one who regularly works on railway power systems may
actually have in their kit a 'test lamp' for 750v supplies.

IIRC, it's a bank of lamps "just in case" one or two lamps have
blown

I'm sure I remember Peter Purves going into the Underground with a
maintenance team for Blue Peter in the 1970s, and being shown a bank
of twelve light bulbs "just in case".

(I also remember his reference to "the hiss of opening doors", despite
there being no such thing till the D78 stock [or since?]. In those
days the doors all opened silently and popped before closing.)

They all hiss when the seals are worn (and the door motors aren't
electric).

D stock has always been difference because of the different door actuator
design from other stocks.

--
Colin Rosenstiel

Crossing London tube tracks
 

On Apr 7, 10:15*pm, Charles Ellson wrote:
On Mon, 7 Apr 2008 02:32:13 -0700 (PDT), MIG





wrote:
On 7 Apr, 08:34, Stimpy wrote:
On Sun, 6 Apr 2008 21:18:22 +0100, Matthew Geier wrote

*Some one who regularly works on railway power systems may actually have
in their kit a 'test lamp' for 750v supplies.

IIRC, it's a bank of lamps "just in case" one or two lamps have blown

I'm sure I remember Peter Purves going into the Underground with a
maintenance team for Blue Peter in the 1970s, and being shown a bank
of twelve light bulbs "just in case".

(I also remember his reference to "the hiss of opening doors", despite
there being no such thing till the D78 stock [or since?]. *In those
days the doors all opened silently and popped before closing.)

They all hiss when the seals are worn (and the door motors aren't
electric).

As I remember, in the 1938 to 1972 generations (that I was familiar
with), the doors would open silently (apart from the rumble of
movement). But they would pop before closing. The pop before closing
might be accompanied by a hiss if they were worn, and it was pretty
much as useful as bleepers for the punters, if unintentionally.

The 1973 and C77 stock made very little noise when opening or closing
(although I think there was still a delay before closing when the pop
would have been).

The D78 stock was very different (as mentioned in another reply), in
that it hissed loudly and continuously during both opening and
closing.

The modern stock makes very little air-related noise at all.

Anyway, whoever did the write-up for Blue Peter at the time obviously
never travelled on the Underground and was trying to be poetic.

Crossing London tube tracks
 

In article M8OdnaePt_78GmfanZ2dnUVZ8sTinZ2d@plusnet, Andy Burns
scribeth thus
On 07/04/2008 10:32, MIG wrote:

I'm sure I remember Peter Purves going into the Underground with a
maintenance team for Blue Peter in the 1970s, and being shown a bank
of twelve light bulbs "just in case".

yes I remember that too, presumably 4 parallel sets of 3 lamps in series
so the -240/+410 gives each lamp about 250V?

I thought an 'eff off size shorting bar was the best insurance;!...
--
Tony Sayer

Crossing London tube tracks
 

On Tue, 8 Apr 2008 09:52:47 +0100, tony sayer
wrote:

In article M8OdnaePt_78GmfanZ2dnUVZ8sTinZ2d@plusnet, Andy Burns
scribeth thus
On 07/04/2008 10:32, MIG wrote:

I'm sure I remember Peter Purves going into the Underground with a
maintenance team for Blue Peter in the 1970s, and being shown a bank
of twelve light bulbs "just in case".

yes I remember that too, presumably 4 parallel sets of 3 lamps in series
so the -240/+410 gives each lamp about 250V?

I thought an 'eff off size shorting bar was the best insurance;!...

It doesn't work if one conductor rail is isolated from the source.
Come to think of it, neither will the lamp which really needs to have
a third connection to 0v to do the job properly.

Crossing London tube tracks
 

In article , Charles Ellson
scribeth thus
On Tue, 8 Apr 2008 09:52:47 +0100, tony sayer
wrote:

In article M8OdnaePt_78GmfanZ2dnUVZ8sTinZ2d@plusnet, Andy Burns
scribeth thus
On 07/04/2008 10:32, MIG wrote:

I'm sure I remember Peter Purves going into the Underground with a
maintenance team for Blue Peter in the 1970s, and being shown a bank
of twelve light bulbs "just in case".

yes I remember that too, presumably 4 parallel sets of 3 lamps in series
so the -240/+410 gives each lamp about 250V?

I thought an 'eff off size shorting bar was the best insurance;!...

It doesn't work if one conductor rail is isolated from the source.
Come to think of it, neither will the lamp which really needs to have
a third connection to 0v to do the job properly.


Well one would short pos and neg to the running rail//s..
--
Tony Sayer

Crossing London tube tracks
 

On Tue, 8 Apr 2008 17:37:04 +0100, tony sayer
wrote:

In article , Charles Ellson
scribeth thus
On Tue, 8 Apr 2008 09:52:47 +0100, tony sayer
wrote:

In article M8OdnaePt_78GmfanZ2dnUVZ8sTinZ2d@plusnet, Andy Burns
scribeth thus
On 07/04/2008 10:32, MIG wrote:

I'm sure I remember Peter Purves going into the Underground with a
maintenance team for Blue Peter in the 1970s, and being shown a bank
of twelve light bulbs "just in case".

yes I remember that too, presumably 4 parallel sets of 3 lamps in series
so the -240/+410 gives each lamp about 250V?

I thought an 'eff off size shorting bar was the best insurance;!...

It doesn't work if one conductor rail is isolated from the source.
Come to think of it, neither will the lamp which really needs to have
a third connection to 0v to do the job properly.


Well one would short pos and neg to the running rail//s..

That would be nearly the same as earthing of all phases on overhead
lines (seven clamps/clips and a spider of cable) but not quite. The
"box of eggs" is OK as long as someone looking at it realises that if
someone working further down the track has left off (or chopped) the
feed from one pole then the other could still be live if the supply
was switched on. It seems more of a warning that trains could approach
than of electrical safety; the FO short-circuit bar will stop the
trains (other than diesel/battery/etc.) but the usual rule about
treating anything as live unless it is obviously earthed seems to be
the main defence.