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1940/50/60s UK Power Boxes with 'GRS' 'NX' Panels

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

Unread postby Aitken » Sun Sep 21, 2008 8:18 pm

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Unread postby SDL » Sun Sep 21, 2008 8:30 pm


I'd always assumed your username was a reference to Jno. Aitken, the prolific Scottish author of many signalling-related books circa the 1940s (such as "The Railway Signalman, incorporating The Signalman's Pocket Book"). :) Guess I was wrong!

Nice pics, by the way.
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Unread postby Alan Norris » Mon Sep 22, 2008 7:47 am

SDL wrote:

I'd always assumed your username was a reference to Jno. Aitken, the prolific Scottish author of many signalling-related books circa the 1940s (such as "The Railway Signalman, incorporating The Signalman's Pocket Book"). :) Guess I was wrong!

Nice pics, by the way.


I used to have one of Jno. Aitkens books - my mum lost it in a house move :shock: :cry: :cry: :cry:
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Unread postby Mike Hodgson » Mon Sep 22, 2008 8:29 am

If you are looking for a copy, they come up on ebay from time to time, and the price is generally modest.
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Unread postby Mad Mac » Mon Sep 22, 2008 3:06 pm



Thanks, I knew I'd seen some colour ones somewhere!
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Unread postby StevieG » Thu Sep 25, 2008 12:49 am

Richard Pike wrote:Was Potters Bar a MetV GRS installation? This came my way last night..

http://richard2890.fotopic.net/p53659724.html

Note that it shows double track to Greenwood.

Certain that it was MetV GRS.
As is no doubt obvious, your photo is of the diagram panel from the console desk, having (apart from those for its own fixings) holes only for the entrance switches, exit buttons (where not combined with an eN.switch), and the singular route set lights.
As the double track at the right-hand end demonstrates, this is the early (presumably the first) of these installed here : - My impression has always been that the box opened, with the quadrupling through the station, in about 1954, whereas the quadrupling south to Greenwood was '59 if I remember rightly, when a replacement for the one in your photo would have been needed.
Colour? - The later one was a green of some sort, a bit darker than in your photo I would've said, though yours has had plenty of time to fade up to a lighter shade. Pretty sure the main diagram and all the other console panels were a fairly dark green.
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Unread postby StevieG » Thu Sep 25, 2008 1:06 am

Mike Hodgson wrote:
StevieG wrote:
John_S wrote:Interesting to hear what K Barber says about the signal indications at Stratford.



* - The moving point indicators were not infallible, and could stick. I've heard of one definite occasion at PB where, after a train was turned in, Up Fast to Slow, the signalman held approaching Up Slow trains in a queue and continued running other UF trains into the Slow, when convinced the UF-US crossover would not move back from R to N. It was the S&T lineman who found that the points were working fine, detecting in either position without problem, and the only thing wrong was the point indicator sticking in Reverse, so if the signalman had tried setting 'straight' routes through it, all signals would have cleared normally.


Ah, but would you advise a signalman to try setting straight routes through a crossover indicating reverse, in the vague hope that it was just faulty indication ? The lineman should be competent to determine whether or not there is anything more to it, but do you want signalmen trying work out where the fault is ?

By modern thinking, I would have to say no ; ... but 40 years ago? - I rather think that many signalmen would have tried it : Then, as operators were often assured by engineers to have trust in the interlocking, a genuine such wrong side failure could have been virtually unthinkable.
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Unread postby StevieG » Thu Sep 25, 2008 1:08 am

kbarber wrote:StevieG talking of Potters Bar:
...a single white route-set light on the immediate approach to every exit button.

Barking had similar lights but with a quite different purpose. When an entrance switch was operated, those white lights became illuminated for every potential exit. IIRC all were extinguished once an exit was selected.

My word! Never heard of such an arrangement.
Surprising if they did ALL go out once an exit was selected : At Potters Bar, the illumination of one of these was the only constant indication of a route set.
If you're right, did Barking use some other means of showing a route set ?
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Unread postby kbarber » Thu Sep 25, 2008 8:40 am

StevieG talking of Potters Bar:
...a single white route-set light on the immediate approach to every exit button.

Kbarber replied:
Barking had similar lights but with a quite different purpose. When an entrance switch was operated, those white lights became illuminated for every potential exit. IIRC all were extinguished once an exit was selected.

StevieG:
My word! Never heard of such an arrangement.
Surprising if they did ALL go out once an exit was selected : At Potters Bar, the illumination of one of these was the only constant indication of a route set.
If you're right, did Barking use some other means of showing a route set ?


Perhaps I should've emphasised IIRC; it's just possible that the light remained illuminated for the route actually selected. But at Stratford & Bow Jc I'm pretty certain there was no positive indication of a route set, it would have to be deduced from a signal being clear or points showing locked, so it's equally possible Barking was similar.
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Unread postby Keith » Fri Sep 26, 2008 11:10 pm

StevieG wrote:
Mike Hodgson wrote:... but do you want signalmen trying work out where the fault is ?

By modern thinking, I would have to say no ; ... but 40 years ago? - I rather think that many signalmen would have tried it : Then, as operators were often assured by engineers to have trust in the interlocking, a genuine such wrong side failure could have been virtually unthinkable.

Going back to Perth Box, when it opened on 25/2/1962, I was once told it was a particularly frosty night and the point heaters hadn't been fitted. The signalman, without any prompting, prevented any points from failing by constantly turning the point switches normal and reverse throughout the night. How many would think to do that these days?
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Unread postby John_S » Tue Sep 30, 2008 9:35 pm

Some questions about the Perth panel - looking at Aitken's photos, especially the one of the South Fringe panel:

(1) is this an N-X panel? (I assume yes - but it looks rather similar to Rochester, where I understood you set different routes by turning the entrance switch in different directions)

(2) it appears that signals with only one route still have an exit button as well as the entrance switch - is this really so, and why?

I assume signal indications are shown by a coloured lamp, located on the track just in advance of the entrance switch
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Unread postby SDL » Tue Sep 30, 2008 9:50 pm

John_S wrote: (1) is this an N-X panel?
It is.

(2) it appears that signals with only one route still have an exit button as well as the entrance switch - is this really so, and why?
Illumination of the exit button is an indication that the route is set.

I assume signal indications are shown by a coloured lamp, located on the track just in advance of the entrance switch
Yes.
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Unread postby StevieG » Wed Oct 1, 2008 1:08 am

Coming back to the 'GRS' element of this thread :

[ From thread "historical >> Signalling Equipment Ltd., Potters Bar, Middlesex" ]

Richard Pike wrote: Was Potters Bar an NX panel? ....
....It's just that i can't see how it worked..

http://richard2890.fotopic.net/p53659724.html

Can someone help me understand it? .....
_________________
Richard..
and
signalman wrote:As I remember it (and it is a few years since I did just one shift there as telegraph boy) you turned the entrance knob and pressed the exit to set a route.

Turn the knob back to cancel.

John
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John Webb wrote:
JRB wrote:
John Webb wrote:The little I can see suggests the switches were standard industrial ones which are still available from the likes of RS Components.
Standard ! That'll be the day. Trying to source compatible ones is bad enough, but standard is an impossible ideal.


Well, the hole sizes and the anti-rotation lug are pretty universal - I admit the actual switch appearance may differ! :)

The eNtrance switches appeared to be exactly the same at Potters Bar*, as those seen at Brunswick (photo), Stratford, Bow Junction, Mile End (photo) and Barking (BTF film), [except that the older boxes had the red/green signal indications shown through the translucent static centre portion of the switch; at the others where the indications were shown by other means, the centres were opaque], so if the switches were 'standard industrial' / RS Components, seems they would have had to have been available from at least about 1948 (earlier? [Brunswick]) - 1960/1.
* - (except Potters Bar had eXit buttons in the centre of several of the eNtrance switches.)

In looking at Richard's photo of the console panel, and remembering that the switches and buttons for both directions were all placed along the lines, and that it's impossible to tell from the holes which switch/button applied to which direction (although I do know), the largest holes with the anti-rotation notches were for eNtrance switches.
The medium sized holes took eXit buttons where the buttons were the same large-ish size as all of the eXit buttons on the older panels, like Bow, and Stratford, i.e., at Potters Bar, these were where there was a need for an eXit button but not an eNtrance switch.
The smallest holes were for the singular route-set lights, one on the approach to each exit button.

As the D.I. has said, a route was set by turning the entrance switch then pressing the desired entrance button. The entrance switches for main signals were red (dark in the B&W picture); those for the ground shunt signals (position-lights at PB) were yellow (the light ones in the B&W picture).
All eXit buttons at PB, whether the standard (independent button) size where there was no eNtrance switch, or the thin type (mounted in the centre of a co-located eNtrance switch), were black with a white direction arrow.

Every eNtrance switch had a small circular white pip on the side of its top edge, so that the switch's position (Normal or Reverse) could be recognised at a glance. When the switch was Normal the pip was in line with the track, facing towards train movements to which its signal applied. To start route selection, the switch was turned up through 90 degrees (pip goes to the top) for a main route (red switch), or down 90 for a shunt route (yellow switch), or subsidiary route from a main signal (e.g., to a siding).
When a route was successfully called, the route light immediately before the route's eXit button illuminated, remaining I think, until the last part of the route was released.

So what about the rest of the basic indications?
Point detection, - N., R., and undetected, - was of course shown by the 'triangles' of the moving electro-magnetic point indicators, which here at PB were up on the separate main indication panel, along with the red/green and red/white signal indications, and the track circuit boundaries and occupied indications (one long, narrow, (2-bulb?) white indication per T.C.).
So when a route was set, the visible evidence was ; the relevant white route light lit on the console, the white pip of the entrance switch at 90 degrees away from being in line with the track, following the 'wide' line width between the entrance and exit signals up on the diagram as formed by the positions of the point indicator(s), and, if the signal was 'off', its green or white light on the diagram panel.
Each of the 3-position individual points switches on the near-upright section of the centre console had, I think, a white 'locked' light ; they also might - but I'm far from sure that I'm remembering correctly about this after so long - have had N and R white lights, unlike the earlier 'vertical' panels, but don't quote me on that.

(Richard, Hope that's of help.)
Last edited by StevieG on Sat Oct 11, 2008 10:09 am, edited 1 time in total.
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Unread postby Richard Pike » Sat Oct 11, 2008 8:54 am

Sorry for the slow reply on this one. I had seen a Potters Bar diagram on my travels and it took a while to track it down. I guess this panel is one i wont be rebuilding...

http://richard2890.fotopic.net/p54182772.html

I may upload it as three images if anyone wants better detail..
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Unread postby StevieG » Sat Oct 11, 2008 10:31 am

Nice one, Richard.

You probably already realise that your photo is of a drawing of the indications diagram 'panel', which I've mentioned before as standing on pillars a couple of feet behind the operating console desk.

Looks like this was a version of its last few years before resignalling swept all that away, because the large gap between the Down Slow (bottom line) and the Down Fast had been occupied by a middle 'reversing' siding, accessible at both ends from the DS (3 ways) and towards the Up Fast across the DF (single slip), and involved four more sets of points and another three position-light ground sigs.
The whole lot went (except the down siding) in about 1973 with the present layout and resignalling and the MV/GRS kit was replaced by a 'York' satellite-style panel coming in for a short time before that got transferred to its designed permanent location in the relay room for emergency control, when New Barnet North took over the PB area using its 'York' panel and TDM remote control.
Then subsequently all went onto the present Kings Cross PSB in '75/6 when New Barnet succumbed and the KX-NB TDM remote control came online (with PB interlocking controlled through both the KX-NB and NB-PB TDMs in turn).

The pictured drawing also shows hints of another interesting point or two, which I may elaborate on later.
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