Signals

THE SIGNAL BOX


Railway signalling discussion

Mixing mechanical and automatic signalling

British signalling of the past (UK, excepting Northern Ireland)

Mixing mechanical and automatic signalling

Unread postby Crepello » Fri Aug 11, 2017 6:38 pm

Good evening; I'm interested in the North London Line in the 1950s, so there would have been parts with the LMS 1930s signalling scheme I believe.

As a person with only a naïve understanding, I'd like to know more about how boxes controlled a section that was, say, fitted with automatic lights for a main line but also had control of a branch section that was mechanically signalled. I.e a facing branch from the main line ( electric signal ) and thence mechanical signals. Would the FPL have been electric, and would it be controlled from the box at the junction or from a box elsewhere?..
I presume the combination of detection and electronic locking assisted where such sections met? hope you learned people out there know some answers!
Cheers
Al
Crepello
Trainee
Trainee
 
Posts: 1
Joined: Fri Aug 11, 2017 6:13 pm

Re: Mixing mechanical and automatic signalling

Unread postby John Hinson » Sun Aug 13, 2017 1:39 am

G'day Al,

There was no automatic signalling on the North London at that time. everywhere was worked on the Absolute Block system. There were some LMS colour-light signals but these were just substitutes for semaphore signals.

I am wondering if you are thinking of the Camden-Watford New Line? The signalling here was automatic except in the vicinity of signalboxes (when switched in). There weren't many interfaces with other signal boxes but in the few instances signals were either slotted (where sections were short) or Absolute Block applied . . . or both. For example, on the City Passenger lines between Willesden New Station and Kensal Green Junction boxes, Absolute Block applied but each box's Starter was slotted as the other's Outer Home - this allowed trains to be freely accepted despite trains being signalled through on the busy main routes at each box.

John
Image
‹(•¿•)›
User avatar
John Hinson
Site Admin
Site Admin
 
Posts: 6745
Joined: Thu Nov 8, 2007 1:13 pm
Location: at my computer

Re: Mixing mechanical and automatic signalling

Unread postby Fast Line Floyd » Mon Aug 14, 2017 9:55 am

Crepello wrote:Good evening; I'm interested in the North London Line in the 1950s, so there would have been parts with the LMS 1930s signalling scheme I believe.

As a person with only a naïve understanding, I'd like to know more about how boxes controlled a section that was, say, fitted with automatic lights for a main line but also had control of a branch section that was mechanically signalled. I.e a facing branch from the main line ( electric signal ) and thence mechanical signals. Would the FPL have been electric, and would it be controlled from the box at the junction or from a box elsewhere?..
I presume the combination of detection and electronic locking assisted where such sections met? hope you learned people out there know some answers!
Cheers
Al

The FPL would have been mechanical if the points were mechanical and such points and FPL's would be worked from the same signalbox that controlled the signal reading over the points. However the detection of the points and FPL would have been electric so as to complete the colourlight signal circuits.

Please don't confuse Electric and Electronic, there was nothing electronic in 1930's signalling.
Graham
User avatar
Fast Line Floyd
Main line box
Main line box
 
Posts: 1613
Joined: Tue May 26, 2009 11:42 am
Location: Raunds

Re: Mixing mechanical and automatic signalling

Unread postby StevieG » Tue Aug 15, 2017 8:56 pm

Fast Line Floyd wrote:
Crepello wrote:Good evening; I'm interested in the North London Line in the 1950s, so there would have been parts with the LMS 1930s signalling scheme I believe.

As a person with only a naïve understanding, I'd like to know more about how boxes controlled a section that was, say, fitted with automatic lights for a main line but also had control of a branch section that was mechanically signalled. I.e a facing branch from the main line ( electric signal ) and thence mechanical signals. Would the FPL have been electric, and would it be controlled from the box at the junction or from a box elsewhere?..
I presume the combination of detection and electronic locking assisted where such sections met? hope you learned people out there know some answers!
Cheers
Al

" .... However the detection of the points and FPL would have been electric so as to complete the colourlight signal circuits. .... "
May I just add though, FLF, that there were instances (not specific to the North London line, also fairly rare I believe, and usually quite old) where colour-light protected mechanical points/FPLs had mechanical detectors, as used for mechanically-worked semaphores.
From these, the signal wires then ended at mechanically-actuated electric contact boxes ('circuit controllers') on, or close to, the signal(s) structure(s), from which electrical circuitry then controlled the colour-light signal aspects.

On the North London line, in 1969 before the severely rationalised Broad Street area layout and signalling was concentrated on BS No.2 Box, I saw that the two Up lines' (admittedly ancient-looking) multi-routed colour-light Home signals at Skinner Street Jn. Box operated in this way (even to the extent of also being mechanically slotted by SSJ and one other box or ground frame for every route).
BZOH

/
\ \ \ //\ \
/// \ \ \ \
StevieG
Double-manned box
Double-manned box
 
Posts: 3002
Joined: Sat Nov 10, 2007 10:30 am
Location: ex-GNR territory in N. Herts.

Re: Mixing mechanical and automatic signalling

Unread postby Fast Line Floyd » Wed Aug 16, 2017 8:16 am

StevieG wrote:
Fast Line Floyd wrote:
Crepello wrote:Good evening; I'm interested in the North London Line in the 1950s, so there would have been parts with the LMS 1930s signalling scheme I believe.

As a person with only a naïve understanding, I'd like to know more about how boxes controlled a section that was, say, fitted with automatic lights for a main line but also had control of a branch section that was mechanically signalled. I.e a facing branch from the main line ( electric signal ) and thence mechanical signals. Would the FPL have been electric, and would it be controlled from the box at the junction or from a box elsewhere?..
I presume the combination of detection and electronic locking assisted where such sections met? hope you learned people out there know some answers!
Cheers
Al

" .... However the detection of the points and FPL would have been electric so as to complete the colourlight signal circuits. .... "
May I just add though, FLF, that there were instances (not specific to the North London line, also fairly rare I believe, and usually quite old) where colour-light protected mechanical points/FPLs had mechanical detectors, as used for mechanically-worked semaphores.
From these, the signal wires then ended at mechanically-actuated electric contact boxes ('circuit controllers') on, or close to, the signal(s) structure(s), from which electrical circuitry then controlled the colour-light signal aspects.

On the North London line, in 1969 before the severely rationalised Broad Street area layout and signalling was concentrated on BS No.2 Box, I saw that the two Up lines' (admittedly ancient-looking) multi-routed colour-light Home signals at Skinner Street Jn. Box operated in this way (even to the extent of also being mechanically slotted by SSJ and one other box or ground frame for every route).

Indeed Steve I had thought of adding this but decided not to muddy the water.
Graham
User avatar
Fast Line Floyd
Main line box
Main line box
 
Posts: 1613
Joined: Tue May 26, 2009 11:42 am
Location: Raunds

Re: Mixing mechanical and automatic signalling

Unread postby StevieG » Wed Aug 16, 2017 11:38 am

[quote="Fast Line Floyd[/quote]
Indeed Steve I had thought of adding this but decided not to muddy the water.[/quote]Hmm; probably a fair point Graham.

Crepello, I hope you gain the understandings that you seek from these 'muddied waters'.
BZOH

/
\ \ \ //\ \
/// \ \ \ \
StevieG
Double-manned box
Double-manned box
 
Posts: 3002
Joined: Sat Nov 10, 2007 10:30 am
Location: ex-GNR territory in N. Herts.


Return to Signalling - historical

Who is online

Users browsing this forum: No registered users and 3 guests