NX Panel - Ground Frame Releases

[NickLocke]

Probably a question for those actually working an NX Signalling Panel (my question is based on some photographs of Kings Cross).....

I know that the individual point control switches are three position and are normally left in the centre position for route setting. Indications are Normal/Reverse and "Out of Correspondence". Please tell me if I have got that bit wrong.

Ground Frame releases (such as Watton at Stone) have three indications - N/F/R - presumably Normal, Free and Released. I'm not sure whether the switches are two or three position (unlike the point switches which are usually centered, the release switches seem to sit in "N" normally).

Please could someone talk me through the operation of a ground frame release switch and how the indications change?

Thanks.

 

[ralphchadkirk]

Yes, your Normal, Reverse and OOC explanation is correct.

As far as I am aware on an NX panel, the switch usually resides in Normal - no release given. The signalman will move the switch to Free if he wants to give a release, and when the GF operator takes the release the signalman will see a Released indication.

I may be wrong on that, but as far as I am aware that is the way it is done.

 

[Metroland]

Normal - Keys locked, signals can be cleared and worked normally.
Free - Keys free to be taken out, signals cannot be cleared.
Released -Keys out, sometimes flashing indications on panel. But signals cannot be cleared and points can be worked on location.

Some ground frames vary and use mini panels and so on and not keys.

 

[NickLocke]

Thanks both - I wasn't expecting one response that quickly, let alone two!! I'm a lot clearer now, but still a gap or two.....

The usual position is that the switch points to "N" and the indication is "N".

When the panel operator wants to give the release, he moves the switch to point at "F" .... or is that "R" ?? The panel indication then changes to "F". It's this that makes me think the switches are probably only two position (only capable of being set to "N" or "R")?

When the ground frame operator takes the release, the "F" indication on the panel changes to "R".

Presumably when the groundframe operator has finished, he locks up the frame again and the panel indication returns to "F" - but he could still unlock the frame again if necessary. Then the panel operator returns the switch to "N" which takes away the release and the indication will also return to "N".

I'd guess that if the panel operator moves the switch back to "N" while the ground frame is still in use, the "R" indication will remain until the frame is locked up and, at that point, the indication will go back to "N". Perhaps some "out of correspondence" type flashing if that happens?

 

[ralphchadkirk]

The switches are two position, normal and free, but with three indications.

 

[NickLocke]

Another blisteringly fast response - thank you!

Two position with three indications makes sense. On the photo that I have, the indicators are in the order N/F/R and I can see that when normal, the switch points to "N".

Do we know whether the second position of the switch is pointing to "R" or "F"?

I'm probably getting far too detailed now!!

Thanks.

 

[Signalfixer123]

The Ground Frame switch can be identified by it's colour-brown.
It has two positions-Normal and Reverse.
There are three indications-Normal, Free and Reverse.
With the Ground Frame release switch in the Normal position, a Normal indication can be expected, provided the Ground Frame is detected Normal.
Provided no route is set though the Ground Frame points, then the Free indication will also be lit.
Once a route is set through the Ground Frame points, the Normal indication remains lit, but the Free indication goes out.
When there is a requirement to release the Ground Frame, the signaller will firstly cancel the route. Once the route lights have extinguished, the Free indication for the Ground Frame will light.
The signaller then turns the release switch to Reverse and the Normal indication will extinguish and the Reverse indication will light. The Free light is still lit at this time.
When the interlocking responds to the turn of the Ground Fame switch from Normal to Reverse, a Free( or Released) light will light up on the Ground Frame.
The shunter will then press the plunger on the Ground Frame and reverse the release lever. The reversal of this lever will extinguish the Free light on the signaller's panel, thus indicating to the signaller that the release has been taken.
The signaller is now unable to take back the Ground Frame until the shunter has finished using it.
When the shunter has finished using the Ground Frame, the release lever is returned to Normal in the Ground Frame. This lights the Free light on the signaller's panel.
The signaller can now turn the Ground Frame release switch to Normal and provided the points are correctly detected and the release lever is fully home the Reverse light will go out and the Normal light will light up. The Free light will remain lit until the signaller sets a route through the Ground Frame points.
Once a route is set, the Free light will go out.
The Free light will flash if the Ground Frame detection is lost. If this happens, then the entrance signal to the route through the Ground Frame points will revert to Danger.
Hope this helps-it's the GEC way of doing things so you should bear in mind that Westinghouse or Free wired interlockings may achieve the same thing slightl differently.

 

[Old Timer]

Kings Cross is a GEC panel

 

[Signalfixer123]

Actually, not wanting to splt hairs, Kings Cross panel is a Henry Williams panel!!
Which in turn is connected to either:-
1/. A GEC interlocking(Kings Cross)
2/. A TDM system(to all other interlockings on the Kings Cross control area).

 

[Old Timer]

OK pedant (). I did know that as we had to buy some tools and parts from them when we altered the panel and the interlocking a while back.

The various Interlockings are GEC Geographical, each equipped with a local nx panel for local operation.

 

[NickLocke]

Thanks both - and apologies for starting the hair-splitting session!!

It would probably make sense for me to give a bit of background as to what I am up to (then you can just call me sad instead of splitting your hairs!!).

Back in the dark ages (1970s) I constructed a simulator/model of an NX panel. It was broadly modelled on Hertford North although, when I started, there was still a box at Hertford albeit that the frame had gone and been replaced with a panel (of sorts). In those days, it was relays and ex-GPO uniselectors to drive the model. The trickiest part was the panel buttons - it's amazing what can be done with perspex rods, microswitches and miniature bulbs!

For some reason (not sure why) I suddenly find myself with a renewed interest and am contemplating embarking on the same route - this time covering a slightly bigger area and using a PC to do the simulation with various bits of connectivity to handle inputs (buttons/switches), outputs (indicators) and the simulation (locking and a timetable).

Interestingly enough, I approached Henry Williams "back then" - and they told me that Domino equipment was sold only through GEC (does that let you two have a truce?).

I have just contacted them again, as I know they can now sell "spares" directly rather than through GEC - I have no plans to go "full blown" Domino, but reckon that using the "real" buttons would make a lot more sense than going down the perspex rod route again. So far they have ignored me - and they are due for a chaser.

Assuming you are not now laughing too much at the whole idea, any more background information like that useful stuff on the ground frame releases would be very welcome.

PS SignalFixer - sounds like both the point and ground frame switches move the "same distance", but the ground frame switch only has "left" and "right" whereas the point switch also has a "middle" position?

Cheers guys,

Nick

 

[ralphchadkirk]

The point switch is the same - two positions, three indications.


Good luck with your project, I would love to have a play on it!

 

[NickLocke]

The point switch is the same - two positions, three indications.!

I don't think so - certainly not on a GEC (or is that HW!) panel. There, the switch sits in the middle (pointing to the "OOC" indication) to allow the points to be controlled by routes being set through them.

Setting the switch to "N" or "R" moves the points to that position and fixes them there - routes can be set through the points if they are lying the right way; but the route setting process cannot move the points. Normal route setting is allowed once the switch is back in the middle.

I believe the technique of forcing the points to "N" or "R" is used to "persuade" the route setting process to go through a non-preferred route on occasions.

Good luck with your project, I would love to have a play on it!

Well, if I ever get there - all you helpful souls will be most welcome!

 

[Old Timer]

NickLocke
I think you will find that the "proper" panel buttons (the slim ones) have been withdrawn and replaced by these awful chunky ones.

If you are having problems with Henry Williams, I may be able to help although getting parts is harder by the year seemingly.

My Signalling Project Engineer was looking at a slim alternative to the big buttons some time back but I haven't asked him how he has gotten on because I have been involved on other work.

If you are going to do a real pucker job, you will need a panel artist to paint the colours

Might cost you a few pints though !

In the SGE/GEC boxes I worked many many years ago the switch knob was the same, but the GF Release only had the two positions, there was no middle position. Remember also that the SGE panels had separate repeater panels from the route setting panel which was a pedestal set in front of the display panel. You could physically walk around between the back of the route setting panel and the display panel.

 

[ralphchadkirk]

I don't think so - certainly not on a GEC (or is that HW!) panel. There, the switch sits in the middle (pointing to the "OOC" indication) to allow the points to be controlled by routes being set through them.

Setting the switch to "N" or "R" moves the points to that position and fixes them there - routes can be set through the points if they are lying the right way; but the route setting process cannot move the points. Normal route setting is allowed once the switch is back in the middle.

I believe the technique of forcing the points to "N" or "R" is used to "persuade" the route setting process to go through a non-preferred route on occasions.


Well, if I ever get there - all you helpful souls will be most welcome!

My mistake - you are quite right
If you ever want help or anything from me, don't hesitate to email me.
Edit - Parcsigns in Cornwall are very good, they have just produced a panel diagram for a new signalbox I know. Maybe not the painting!

 

[NickLocke]

Thanks both for the pointers and for the offers of help....

I wil keep you posted with progress (likely to be slow!).

Cheers

 

[Metroland]

The point switch is the same - two positions, three indications.


Good luck with your project, I would love to have a play on it!

Indeed so, Henry Williams Swiss Integra ones I've worked certain have.

Bit of trivia, if you ever go in the Swiss transport museum in Lucern, there's a 'preserved' example of that type of panel for Swiss railways. Looks very familiar to those used to (especially) Western Region panels.

 

[Greeny]

I think you will find that the "proper" panel buttons (the slim ones) have been withdrawn and replaced by these awful chunky ones.

Oh yes OT. the chunky ones are awful - they have a sharp flange and they cut my fingers to shreds unless I'm careful. Somebody helpfully suggested that I do be careful. Which just flew up my nose as I'm a Signalman, not a blinking acrobat.

G

 

[Signalfixer123]

OK pedant ().

That's just a bit of banter between two professional railway men-there ain't gonna be a fight!!

Mr Locke, if it is any help I might be able to help you with part numbers for the Domino components. They are all still available.

Regards,

SF123.

 

[Old Timer]

That's just a bit of banter between two professional railway men-there ain't gonna be a fight!!

Mr Locke, if it is any help I might be able to help you with part numbers for the Domino components. They are all still available.

Regards,

SF123.

I say chap !

Have you come across the supplier of the new slimmer buttons ??

 

[Signalfixer123]

No, I haven't.

I ordered a boxful of button repair kits about three years ago, and got the standard type of button in the kits.
Interestingly, the stirrup contacts are now alloy vice brass.

The chunky ones(Swisstacs) are not my favourite button-they are very easy to break, as well as having sharp edges. We have some emergency GEC manufactured panels in the relay rooms where Swistacs have crept in-and they look well out of place.

 

[Old Timer]

No, I haven't.

I ordered a boxful of button repair kits about three years ago, and got the standard type of button in the kits.
Interestingly, the stirrup contacts are now alloy vice brass.

The chunky ones(Swisstacs) are not my favourite button-they are very easy to break, as well as having sharp edges. We have some emergency GEC manufactured panels in the relay rooms where Swistacs have crept in-and they look well out of place.

Ah, so the older type are still about, that I think is good news. I always prefer the older type, as you say these new ones are truly awful. I believe they come from control panels used in other Industries where thye do not get the same sort of frequent use as ours.

Have you seen the Balfour Beatty Technologies new replacement interlocking system which is in effect an electronic version of the GEC geographical interlocking ?

They let me have a play with it about two years ago. Its absolutely brilliant and has none of the issues that "normal" SSI has in respect of design and modification.

If you want to go and have a look at their centre at Derby sometime I can organise that. They are truly splendid chaps and I know they will make you very welcome and will have the clever technical guys on hand to answer any queries.

 

[Signalfixer123]

We spoke about this over a year ago, OT.

I haven't had chance to make contact with the gentleman yet, as it is getting harder for me to "Escape" for a day to investigate new technology.

I do, however, have contact with another firm who are very close by, and might have the opportunity to visit them in the near future. If that happens, then I might be able to kill two birds with one stone-if I'm still there. (I've ticked the Yes box). I'll let you know if that opportunity arises.

 

[Old Timer]

Thanks for the update, chap!

 

[NickLocke]

SignalFixer, I've pinged you a PM about these pesky switches and their part numbers.

Since then, I have also found what I suspect to be the "fat" Swisstac switches here. Interesting that the bezels only seem to be available in grey or black though?!

I have discovered that switch + button + bulb comes to around £50 + VAT. Ouch! Does that sound right?

All thoughts welcome.

 

[NickLocke]

Any chance of a quick moment of gap-filling please chaps. I'm trying to complete my list of escutcheon/bezel colours for the buttons:

Main Signal Entrance (or Entrance/Exit) Button - Red
Subsidiary Signal Entrance Button - Yellow
Exit Button (eg at the far end of a bay plaform) - 1?
Automatic Button - Light Blue
Emergency Replacement Button - 2?

I'm guessing at:

1 - Red because it's the exit from a "main signal route"
2 - Red because it's controlling a "main signal"

Thanks muchly.