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After a recent trip to Didcot I spotted something else that I need to make. This time it is for the layout rather than rolling stock and it needs to be installed before too much of the track is detailed. I've seen someone else make this size of feature work in 2mm scale already and I'm hoping that the LEDs I've ordered will be small enough to fit inside the model, because I'll be disappointed if I cannot make it light up. If not then this will possibly die a death. If so then it will still be a trial to make this well.

 

All will be revealed if progress can be made but can you guess what it is yet?

Edited by richbrummitt

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Signal cabin

 

Think smaller. The example at Didcot is in a corner under a small tree.

Edited by richbrummitt

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Hi Rich,

 

Is it a set of broken King wheels?

 

I'll get my coat...

 

All the best,

 

Castle

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Hmmmm...

 

Well, as my name is tagged I am guessing its something I have done? Signals?

 

M :)

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Hmmmm...

 

Well, as my name is tagged I am guessing its something I have done? Signals?

 

M https://www.rmweb.co.uk/community/uploads/emoticons/default_smile3.gif

 

Yes. More specifically the GWR non-independent style of ground signal of the 19th century. There is one of these under a very small tree near to the transfer shed at Didcot.

 

Hopefully the 0402 package size of the LEDs will fit inside a 1mm diameter hole just over 1mm long, otherwise it could be back to the drawing board. I ordered them from a German site I think you used for yours and they were the smallest I could find. I've prepared some drawings from those that featured in the Broad Gauge Society literature many years ago but am waiting to start making parts until the LEDs arrive so I can be sure of the size.

 

 

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Ahhhh, not a 60XX wheel set (heavy use style) then...

 

I did wonder what te LED was for - perhaps to represent the gas torch of the guy cutting them up in Barry!

 

All the best,

 

Castle

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Now the beans are out of the tin I've updated the title and description to more accurately reflect the content.

 

I've had an email that, if I could read German I would understand but, I think tells me that they have sent me some LEDs. :yes:

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The LEDs arrived very quickly and it's a good job I ordered spares because the carpet monster got in there for one as soon as I started to peel back the packaging! These really are a pig to hold and solder by hand. I have got one soldered up ready for a quick test now after a few false starts and some choice words. I hooked it up to the diode test on the multimeter and there was light :dance:

Edited by richbrummitt

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I'm not sure that this is holding anyone's interest, apart from Castle. Maybe it's due to lack of pictures? Here is the rough plan knocked up in CAD:

 

post-8031-0-35000700-1344947676.png

 

On the left is the assembly and on the right a cross section. Rather than having an arm this type of signal has the top portion swiveling around to show either red or green/white* faces with corresponding lenses to the engine driver. Due to the fact that they were connected into the switch operation they actually only tell the driver what route is set.

 

The small white cuboid at the top centre of the right hand view is the LED. This is attached to the central tube, with 0.3mm ID and 0.5mm OD, which is fixed and used for one electrical feed. The top will be file down, except for a small portion bent around at the back to fix to the solder pad on the back of the LED (this looks a bit odd in the drawing). Inside this is an insulated wire for the other electrical feed that I will probably have to cannibalise a cheap or redundant motor for. Some superglue should hold this central assembly together as required. Around this tube will be a further tube (0.8mm OD with the ID opened up to be a nice running fit on the assembled inner tube) attached to the rotating head of the signal. This will be made from either steel or brass and is 1.5mmOD so I can centre drill to at least 1mmID to create enough space for the LED assembly. This rotating outer assembly has an operating arm beneath the base board to attach with linkages into the TOU (turnout operating unit). In the drawings the very top of this part is not shown. It will have to be added afterwards and needs to be removable in the case I have to change the LED because the central assembly cannot be made to fit down the 0.5mmID tube because the LED is a bit fatter than I thought it would be. The rotating outer assembly will pass through the base. I'm currently thinking through how to make this part and how much detail I want to incorporate of the originals ribbed casting. There also needs to be some method of fixing the base and the inner assembly together and I'm thinking that through too, hence it is not in the drawing yet. The 0.8mm tube is over scale for the bottom of the pivoting section but I don't see there is much scope for improvement there.

 

Some pictures of the prototype will follow soon to help you make further sense of it. I haven't downloaded them from the camera yet.

 

edited after corrections below. *we're not sure about this but it is quite likely the faces were red and white, not red and green as the photos in a later post show.

Edited by richbrummitt
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I'm not sure that this is holding anyone's interest...

I'm keeping an eye on it and rather wishing I had an excuse to build one myself.

 

btw, "non-independent" is a bit of a mouthful, rather like "un-rebuilt". I thought they were normally called "dependent disks"?

 

Nick

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I'm keeping an eye on it and rather wishing I had an excuse to build one myself.

 

btw, "non-independent" is a bit of a mouthful, rather like "un-rebuilt". I thought they were normally called "dependent disks"?

 

Nick

 

I'm not sure what they were usually called: there doesn't seem to be a lot of information on them. Adrian Vaughan's book has a picture and a brief description. I have some photographs from a fellow 2mmSA member taken many years ago, some of my own, and a drawing acquired from (I think) a BGS journal and that is it. Fortunately a fully dimensioned drawing and a handful of photographs is plenty to go on in this case. Maybe I should re-lay some of the track in my goods yard on baulks too, even though I don't have photographic evidence for that particular location on the line?

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I'm keeping an eye on it and rather wishing I had an excuse to build one myself.

btw, "non-independent" is a bit of a mouthful, rather like "un-rebuilt". I thought they were normally called "dependent disks"?

Nick

Official title (to the Ops Dept at any rate) was 'point disc'. The later sort of ground signal being called the 'independent disc' (these being the ones with the miniature cast-iron semaphore arm) while the ones which we are more familiar which actually have a disc face were originally known as the 'new pattern disc'. By the late 1930s the independent disc had become 'independent disc, old pattern' and the new pattern disc had become 'independent disc, new pattern'. These two latter descriptions, plus 'point disc' were still in official use until at least 1972.

 

So in fact there never was such a thing as a 'non-independent disc' (the word 'point' presumably being regarded as descritive enough to indicate that it was independent?

 

Edit to add PS PS Incidentally the entire upper portion of the point disc rotated, not just the outer part (i.e. lamp case) of it however I can see that this would not be possible in an illuminated working model.

 

There is also very clear evidence that at one time, certainly as late as 1920 and possibly later, on some point discs the 'normal' position target was coloured white, not red. This would have made them compatible with the idea of red or white lights in the independent signals and might therefore date from a similar period although - and this is surmise on my part - I suspect originally the target would have been white (what I don't know is if red lights in ground signals/point discs go back further than the 1890s?).

Edited by The Stationmaster
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Thanks, Mike. I've just found some sketches in the new GWW (I think they were in the Slinn edition, too) with them labelled "single point disc", "independent disc" and "independent disc (new pattern)", so it looks like they got that bit right, even if some of that section is a bit shakey.

 

Nick

 

edit: ps, just realised where I got "dependent" from, they use it on the GWS (Bristol) signal pages.

Edited by buffalo

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Thanks, Mike. I've just found some sketches in the new GWW (I think they were in the Slinn edition, too) with them labelled "single point disc", "independent disc" and "independent disc (new pattern)", so it looks like they got that bit right, even if some of that section is a bit shakey.

 

Nick

 

edit: ps, just realised where I got "dependent" from, they use it on the GWS (Bristol) signal pages.

 

I do wish preservationists would check stuff against original source material (most of which in this case is hardly difficult to find - if I can manage to have all of it back to 1920 within a 10ft of my 'puter I'm pretty sure Didcot wouldn't have had too much trouble laying hands on some of it, especially as the most recent reference was issued in 1960 and is commonplace and hardly costly).

But in their defence Didcot have been pretty good on the signalling side although one or two things in those descriptions are incorrect and don't use the proper terminology - which irks when it is so easily got right.

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Edit to add PS PS Incidentally the entire upper portion of the point disc rotated, not just the outer part (i.e. lamp case) of it however I can see that this would not be possible in an illuminated working model.

 

Indeed. I should go back and edit that :oops: If I was working in a larger scale I might have used a grain of wheat bulb or larger LED to avoid the 'problem' with these LEDs only having a single flat face that lights up. I considered this earlier when I remembered that there is also a clear lens in the back of the indicator that requires to be lit. I will have to try placing two LEDs back to back and if I can solder them up like that trial fit them in a 1mm diameter hole. If not I might have to rely on a more sneaky method.

 

Here's my test piece of one LED unlit:

 

post-8031-0-76691500-1344965943.jpg

 

lit:

 

post-8031-0-95754400-1344965937.jpg

 

That's with the full 3v supply. I could try 1.5v reasonably easily, but with 2 LEDs they would have 1.5v each from a 3v supply so I'm not worrying too much right now. They will be far less light when shone through a small hole with a red lens in. The rizla just stops the supply shorting and gives me something to hold!

 

There is also very clear evidence that at one time, certainly as late as 1920 and possibly later, on some point discs the 'normal' position target was coloured white, not red. This would have made them compatible with the idea of red or white lights in the independent signals and might therefore date from a similar period although - and this is surmise on my part - I suspect originally the target would have been white (what I don't know is if red lights in ground signals/point discs go back further than the 1890s?).

 

This sounds 'right'. I'm going to go and do some more reading.

 

Here are some pictures of the one at Didcot, although this has targets for both directions.

 

post-8031-0-98194800-1344965967_thumb.jpg

 

post-8031-0-92021000-1344965975_thumb.jpg

 

That difference and colours aside (maybe I should have changed them to black and white?) this should give the viewer an idea of what it should look like when complete.

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Richard,

 

I have one of these on my P4 layout, this entry in my other blog shows it in operation (http://www.rmweb.co.uk/community/index.php?/blog/834/entry-7308-trefallion-point-control-2/)

 

It is unlit though - as when I originally made it I don't think I could get a LED small enough!

 

I intend making some of these on my 2mm layout (once I start building it) :-) However I probably won't illuminate them!

 

Ian

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I have a colour picture (unable to post it here) of the point disc that was at Radstock, red and green faces. Have you checked the 1936 General Appendix? Gives details of the lights and the colours.

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I have a colour picture (unable to post it here) of the point disc that was at Radstock, red and green faces. Have you checked the 1936 General Appendix? Gives details of the lights and the colours.

 

Thank you for posting. I don't have access to such a document myself. My layout is meant to be set post war - pre grouping so maybe they would have still been white as per Mike's post?

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There's no mention of white in the 1907 painting instructions reproduced at the bottom of this page on the stationcolours site. It makes interesting reading, not least the number of S&T components that should be painted in red, including rodding, rollers, FPLs and the mention of three different red paints, all commercial products from the same source.

 

Nick

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There's no mention of white in the 1907 painting instructions reproduced at the bottom of this page on the stationcolours site. It makes interesting reading, not least the number of S&T components that should be painted in red, including rodding, rollers, FPLs and the mention of three different red paints, all commercial products from the same source.

 

Nick

 

Nice find Nick. I always intended adding it but given that point rodding would be painted red it will be much more obvious if it missing.

 

 

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Here is a copy from the 1960 Regional Appendix, I checked with my 1936 General appendix and the picture is the same. My 1936 appendix is the Avon Anglia reprint - black and white only. The 1936 appendix was in use up till 1960.

 

Always useful going to original sources, I would recommend any GW modeller getting a copy of the relevant appendix.

post-7177-0-57588000-1345065035_thumb.jpg

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I'm back to confusion again. There is green ink on that page, but not on the point discs, only the lower spectacles of the new type independent. The faces are given as red and white and the lights white or red green. What colour do you suppose red green is?

 

It appears that Didcot's example has clear lenses in the red faces and coloured lenses in the green ones? I'm unsure how reliable that is though.

Edited by richbrummitt

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I'm back to confusion again. There is green ink on that page, but not on the point discs, only the lower spectacles of the new type independent. The faces are given as red and white and the lights white or red green. What colour do you suppose red green is?

 

That is why I wrote what I wrote in my last para in Post No. 13 above. So to translate what the Appendix entry says (although it merely repeats what wrote in posts above it does have the advantage of also illustrating it) and referring only to Point Discs they would show either a red or a white light when 'normal' and a green light when reversed; the front target would be either white or red - corresponding to the colour of the light when normal. The reversed target would be green in all cases and the signal would show a green light in that condition. (just be perverse I wouldn't mind betting there were some with red targets that showed a white light but ignore that in terms of your question ;) )

 

Now - and this time I'm repeating something I've already posted - in post 1890s/1900 situations I am presuming that the meaning of a white target/light in a point disc corresponded exactly with the meaning of a white light in an independent disc. What I am not entirely sure of is which, in historical terms, came first but my thoughts on that were explained in Post No.13.

 

Right now, the question is will your model need a red or white target and light in the normal position? Simplest way to find out is to post a diagram or picture of where it will go on your layout and I will tell you which it should be. But there is one simple answer - if it is at a trap point at the exit from a siding it will definitely be red.

 

PS Being pedantic the comment in Post No.23 that the illustration in the 1960 Regional Appendix is exactly the same as that in the 1936 GWR General Appendix is not correct because the GWR did not use yellow arm disc signals and they therefore did not appear in the 1936 GA; they were only added to it in an amendment issued in January 1950.

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