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

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

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

Unread postby StevieG » Wed Sep 17, 2008 9:35 pm

( Moved from 'General Chat', Thread 'Developments at Barking' )

StevieG wrote:Slightly off-topic, but while Barking is being discussed, when the ex-BR/Railtrack section of the box closed with the mid-1990s LT&S Resignalling, I had the impression it was left alone for quite a while, possibly with the old Metrovickers/GRS style NX diagram panel/console with electro-magnetic moving points indicators (wasn't it an unusual variation where the point indicators were down on the console with the route switches/buttons?) also left in place, while the LT portion of the box carried on working as normal.
[ If memory serves, the commissioning of this Barking box (1960?) formed the finale to the BTF film "The Signal Engineers" (see other current "Signalling-Historical" thread, " "Points and Aspects" Vol 8 of the BTF Unit from BF " ).]

Anyone know whether the out-of-use section is still in that state, & whether the panel/console is still there; else what happened to it?


kbarber wrote:StevieG:
the old Metrovickers/GRS style NX diagram panel/console with electro-magnetic moving points indicators (wasn't it an unusual variation where the point indicators were down on the console with the route switches/buttons?)

Stratford & Bow Jc also had indicators on the same console as the switches/buttons, although in their case the panels were near-vertical. In fact I suspect this was the original style, with the separate control & indication panels as a later development. (I take it you have Potters Bar in mind? I must admit I've never seen any decent photos of the panel there.)

StevieG:
Anyone know whether the out-of-use section is still in that state, & whether the panel/console is still there; else what happened to it?

There is a crude plywood casing approximately in the shape of the old panel visible from outside but I have no idea what it contains.
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Re: 1940/50/60s UK Power Boxes with 'GRS' 'NX' Panels

Unread postby StevieG » Wed Sep 17, 2008 10:53 pm

StevieG wrote:( Moved from 'General Chat', Thread 'Developments at Barking' )

StevieG wrote:Slightly off-topic, but while Barking is being discussed, when the ex-BR/Railtrack section of the box closed with the mid-1990s LT&S Resignalling, I had the impression it was left alone for quite a while, possibly with the old Metrovickers/GRS style NX diagram panel/console with electro-magnetic moving points indicators (wasn't it an unusual variation where the point indicators were down on the console with the route switches/buttons?) also left in place, while the LT portion of the box carried on working as normal.
[ If memory serves, the commissioning of this Barking box (1960?) formed the finale to the BTF film "The Signal Engineers" (see other current "Signalling-Historical" thread, " "Points and Aspects" Vol 8 of the BTF Unit from BF " ).]

Anyone know whether the out-of-use section is still in that state, & whether the panel/console is still there; else what happened to it?


kbarber wrote:StevieG:
the old Metrovickers/GRS style NX diagram panel/console with electro-magnetic moving points indicators (wasn't it an unusual variation where the point indicators were down on the console with the route switches/buttons?)

Stratford & Bow Jc also had indicators on the same console as the switches/buttons, although in their case the panels were near-vertical. In fact I suspect this was the original style, with the separate control & indication panels as a later development. (I take it you have Potters Bar in mind? I must admit I've never seen any decent photos of the panel there.)

StevieG:
Anyone know whether the out-of-use section is still in that state, & whether the panel/console is still there; else what happened to it?

There is a crude plywood casing approximately in the shape of the old panel visible from outside but I have no idea what it contains.


I believe the combined vertical control and indications panels were the original style as Bow Junction and Stratford (& Mile End) dated from the period of the 1949 electrification [ also see 'Dutch Signal Boxes' in 'Signalling - Overseas']. Potters Bar was of around 1954, while Barking was a while later, as previously mentioned.

From what I remember hearing of Barking (& perhaps seeing ; - in the BTF 'Signal Engineers' film if I recall), as having, as I think 'the point indicators down on the console with the route switches/buttons', it was not the same as Potters Bar, with which I was acquainted to some degree.

Potters Bar had a separate vertical indications diagram panel, which included the detailed track diagram, individual track circuit limits and indications, separate red and green/white signal 'on'/'off' indications, and the electro-mech.point indicators.
The console desk, aside from its near-vertical centre section and near-horizontal side 'wings' incorporating the indiv.point switches, detonator placers, position-light sigs.and panel indications bright/dim switches, bells and block instrument controls, signal telephones and describer controls, -
the near-horiz. centre main section had a simple static track diagram, on which were mounted (geographically of course), the signal rotary entrance switches and exit buttons*, and a single white route-set light on the immediate approach to every exit button.

* - At this box, any signal which was at the exit of any route, and which was also the entrance of the next route(s), had its exit button-top narrower than normal exit buttons, so that it could be mounted in the centre of the same signal's entrance switch. Though no expert on this subject, I have not heard of anywhere else which had these functions combined in this way.
The exit buttons at signals with no entrance switch or which were not located at a controlled signal, were of the usual larger size, the same as used at Bow and Stratford.
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Unread postby kbarber » Thu Sep 18, 2008 9:18 am

StevieG:
I believe the combined vertical control and indications panels were the original style as Bow Junction and Stratford (& Mile End) dated from the period of the 1949 electrification... I remember hearing of Barking (& perhaps seeing ; - in the BTF 'Signal Engineers' film if I recall), as having, as I think 'the point indicators down on the console with the route switches/buttons'

That's my recollection too; Barking, Stratford & Bow Jc were similar except for the orientation of the panel itself. (It may be relvant that near-horizontal panels seemed quite the thing around 1960; all the LTS panels were of that type as were those on the North East london scheme - Hackney, Broxbourne & Harlow - although the panels in "hybrid" boxes were of necessity vertical.)

One significant difference between the 1949 & 1960 panels was in signal indications. At Stratford, red & green indications were shown through the centre of the entrance switch. At Barking there were very small red & green lights, one each side of the track for main aspects or on the same side for subsidiary aspects, adjacent to the entrance switch. (A signal with both main & subsidiary aspects therefore had 3 indication lamps, but I no longer recall whether the red extinguished when the subsidiary cleared.) One peculiarity - I'm pretty certain a clear subsidiary was indicated by a green light. There was an indication through the centre of the switch - a white light to indicate a lamp failure.
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Unread postby John_S » Thu Sep 18, 2008 7:57 pm

Interesting to hear what K Barber says about the signal indications at Stratford. A few years ago, I was able to photograph the Brunswick NX panel, which is preserved at the NRM in York - and ever since have been puzzled as to how signal and point indications were shown. It doesn't really look as though there are lamps built into the entrance switches, but I could be wrong. Does anyone know the answer? I have put some photos on my website at

http://www.lymmobservatory.net/railways ... agrams.htm

Another puzzle is that the panel at York is certainly not the original one whose photograph appears in various books!
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Unread postby StevieG » Thu Sep 18, 2008 9:09 pm

kbarber wrote:StevieG:
I believe the combined vertical control and indications panels were the original style as Bow Junction and Stratford (& Mile End) dated from the period of the 1949 electrification... I remember hearing of Barking (& perhaps seeing ; - in the BTF 'Signal Engineers' film if I recall), as having, as I think 'the point indicators down on the console with the route switches/buttons'

That's my recollection too; Barking, Stratford & Bow Jc were similar except for the orientation of the panel itself. (It may be relvant that near-horizontal panels seemed quite the thing around 1960; all the LTS panels were of that type as were those on the North East london scheme - Hackney, Broxbourne & Harlow - although the panels in "hybrid" boxes were of necessity vertical.)
Good point; perhaps the Barking style was a variant to give similarity with the other panels of that period from different suppliers.

One significant difference between the 1949 & 1960 panels was in signal indications. At Stratford, red & green indications were shown through the centre of the entrance switch. At Barking there were very small red & green lights, one each side of the track for main aspects or on the same side for subsidiary aspects, adjacent to the entrance switch. (A signal with both main & subsidiary aspects therefore had 3 indication lamps, but I no longer recall whether the red extinguished when the subsidiary cleared.) One peculiarity - I'm pretty certain a clear subsidiary was indicated by a green light. There was an indication through the centre of the switch - a white light to indicate a lamp failure.

You've reminded me that I think the 'off' indication for ground shunt signals at Stratford (shown through the entrance switch's centre of course) was also green, like for the main signals, though the former's switches were yellow rather than red.
I suspect the small indication signal lights you describe for Barking were probably the same as at Potters Bar, though there they were, as I mentioned, on the vertical indications diagram panel [ which also had, in turn above it (virtually reaching the ceiling), a narrow panel of the relatively few twin-cathode ray tube train describer berths, arranged roughly geographically ]. The diagram panel stood on pillars behind the console (there was a narrow gap between them which you could just walk in) with its lower edge about four feet above the floor.
All signals were depicted on the diagram by pseudo-realistic outline symbols, which contained their indications. Signals had separate indications for 'on' and 'off'; main signals - red or green, ground shunts showed red or, I'm pretty sure, white for 'off'. There was only one miniature side aspect to a main signal, for Down Slow to the siding between the DS and Down Fast: I think it displayed the customary min.yellow outside, but have a feeling it was a side green on the diagram.
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Unread postby StevieG » Thu Sep 18, 2008 10:32 pm

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

A few years ago, I was able to photograph the Brunswick NX panel, which is preserved at the NRM in York - and ever since have been puzzled as to how signal and point indications were shown. It doesn't really look as though there are lamps built into the entrance switches, but I could be wrong. Does anyone know the answer? I have put some photos on my website at

http://www.lymmobservatory.net/railways ... agrams.htm

Another puzzle is that the panel at York is certainly not the original one whose photograph appears in various books!
I would confirm what kbarber says about the means of showing signal indications on the original Stratford panel.
Thank you for access to the photos of Brunswick panel ; - much closer views than I have ever before seen. The main route switches (& the exit buttons) look identical to those employed on the Stratford & Bow panels, but I can't tell if, like the latter, the Brunswick switches' dark centre portion is also translucent and could thereby also have had indications displayed through it.
Following on from my details about Potters Bar (PB), where signals needing both an exit button and entrance switch had the two combined in one unit, in cases where an entrance switch did not need an exit button in its centre, the centre portion was opaque and, I think, was white with black direction arrow.
If the Brunswick switches worked through the same arc as those at the later boxes, and I remember correctly, it looks like they're all in the 'set-route' position (white 'pip' at the top), because as I recall, the normal switch position at PB was with the white pip in line with the track, facing approaching trains to which it applied. Main signal switches were then turned 90 degrees up to set a route; shunt signals were turned 90 degrees down; signals with both main and shunt routes would turn either way according to which type of route was to be set.
Incidentally, at Stratford (S) & Bow (B), there were no symbols on the panel for the signals controlled therefrom; the signal switches and centre-indications seemingly considered all that was needed as evidence of a signal's presence and type.

I also note Brunswick's remaining individual points switch (IPS), (No."58"). Those at B & S also had the same appearance : The absence of separate indications for 'N' and 'R' will be noticed, and looks very odd by later conventions.
The 'disc' shaped aperture window at the bottom of the B & S IPSs was transparent, and as I recall, could show red or white.
Seemingly the main indication of N&R detection was intended to be the moving electro-magnetic indicators in the principal track diagram*.
If I remember rightly, the IPSs were normally in the centre position and their bottom aperture showed no light, but when a set of points was relay-locked, e.g., by a route set, white was diplayed through the aperture. When the switch was used, and moved to left or right, red was shown until the points were detected in the position corresponding with the N or R position of the switch.

* - 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.
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Unread postby Mike Hodgson » Fri Sep 19, 2008 8:48 am

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 ?
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Unread postby kbarber » Fri Sep 19, 2008 9:38 am

John_S:
photograph the Brunswick NX panel, which is preserved at the NRM in York - and ever since have been puzzled as to how signal and point indications were shown.


The points indicator is present for crossover 58; those for 59 & 60 are missing. The tongues are pivoted through the hole & can move to lie across one side or the other of what is otherwise a triangular white area. In the photos they look as if they're lying in the mid-position (which did exist & indicated points not detected). Intriguingly the metal tongues of No. 58 indicator are a dark green colour reminiscent of the LNER panel standard; I guess this is a replacement for the original. I wonder where it came from? I notice also the use of a red light at each end of a track circuit, as opposed to the single white characteristic of the LNER panels; I suspect the LMS used the same 2-reds standard on its signalbox diagrams (certainly Acton Wells had that, albeit with an LMR overlay) whereas LNER and earlier BR(E) diagrams used a single white indication. I'd never seen anything other than the LNER standard on one of these panels so the Brunswick example is a real curiosity.
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Unread postby kbarber » Fri Sep 19, 2008 9:50 am

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.
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Unread postby Mackay » Fri Sep 19, 2008 6:15 pm

The Brunswick entrance switches look very similar (except for the red colour of the knurled head) to those used on GRS's North American NX panels in the early 1950s. I have one such panel here at home (from Belt Junction on the Houston Belt & Terminal Rly; installed c. 1951). There is a translucent arrow in the head of the black switch and two small bulbs in the body of the switch project a green or red colour on to the arrow.
The point indicators are essentially the same as Brunswick, with an armature behind the panel moving between the normal and reverse coils. The armature is carried by two miniature ball bearings. Detection is shown by a small red light under the tip of the points. A very delicate little mechanism - easy to see why a line of white lights found favour later.
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Unread postby Mad Mac » Sat Sep 20, 2008 2:47 am

kbarber wrote:When an entrance switch was operated, those white lights became illuminated for every potential exit. IIRC all were extinguished once an exit was selected.


If memory serves, Millerhill worked like this as it was a "true" geographical system. Hyndland and Dumbarton had similar panels, but were more of a "route relay interlocking" in the engine room.
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Unread postby Richard Pike » Sat Sep 20, 2008 9:29 am

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.
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Unread postby Mad Mac » Sat Sep 20, 2008 7:55 pm

Richard Pike wrote:Was Potters Bar a MetV GRS installation?


The background colour and size of switches looks like Perth, which was an SGE job. I'll try to dig up a picture for comparison.
Last edited by Mad Mac on Sun Sep 21, 2008 2:29 am, edited 1 time in total.
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Unread postby Richard Pike » Sat Sep 20, 2008 9:02 pm

I've got a booklet on it... somewhere...
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Unread postby Mad Mac » Sun Sep 21, 2008 5:07 am

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