Cwmhir signaling - Attempting a somersault and rotating discs

[Darwinian]

Thanks Mike. The Rhymney signals I’m modelling were elevated discs so I presume not true running signals. As I’m modelling 1929 (ish) would that mean a white light showing to indicate the clear when the red/disc/lens rotate away?

[The Stationmaster]

21 hours ago, Darwinian said:

Thanks Mike. The Rhymney signals I’m modelling were elevated discs so I presume not true running signals. As I’m modelling 1929 (ish) would that mean a white light showing to indicate the clear when the red/disc/lens rotate away?

Could well be a white light unless the signal had been modified.  However I.m not sure what colour, if any, the RR had used in such signals.

 

I have found a photo of the back of a somersault signal at Aber Jcn c.1905 and the somersault arm definitely has two colours in the spectacle (plus a ring on the arm so presumably applies to a siding/goods line.  There is a subsidiary mounted part  way down the post and bracketed slightly off it.  It appears to rotate as it has the lamp case with no visible target facing any approaching move but at 90 degrees to that there is a round target fixed to the lamp case.  

 

The only other photo I can find of an elevated RR rotating lamp case signal is one at Senghenydd and judging by the position of the points it is clearly at danger with the disc facing any approaching movement and simply the lamp case facing at 90 degrees to it.   So maybe the subsidiary signal at Aber Jcn was showing proceed?  I have found another photo of a subsidiary rotating signal but it is, alas, it's not very clear.

 

Every photo I can find of RR somersault signals shows them with two aspects spectacles- so showing either red or green and the photos date from the early 20th century up to the time not long after the grouping.  As the Rhymney seems to have paid little attention to signalling until forced to do so by the 1889 Act it's possible that its somersault signals always had spectacles capable of showing a colour both when at danger and when 'of'

 

 

[Darwinian]

Thanks again Mike. I'll probably settle on white for "clear" then as that's easier to model!

The Rhymney signals were provided by Makenzie and Holland who also provided similar signals to the New South Wales (IIRC) railway in Australia. There are quite a few pictures of preserved examples of their rotating discs so I have been working on the assumption that the Rhymney ones would have been similar.

[Michael Hodgson]

On 22/01/2023 at 12:19, The Stationmaster said:

The only rotating lamp cases I'm aware of were on ground signals but no doubt someone will know if there were ever used for running signals.

Some of the very early signals worked by a lever at the base of the post did, the sort that rotated the whole signal through 90 degrees using a vertical rod, such as the GWR disc & crossbar ones.  I think the NER may have had something similar at level crossings into the BR era.

 

The "Stop Shunt and Blasting" Signal was mostly used for shunting, but I think it was also used on a few running lines close to quarries.

Something like this ...https://www.ebay.co.uk/itm/184826257366

[The Stationmaster]

20 hours ago, Darwinian said:

Thanks again Mike. I'll probably settle on white for "clear" then as that's easier to model!

The Rhymney signals were provided by Makenzie and Holland who also provided similar signals to the New South Wales (IIRC) railway in Australia. There are quite a few pictures of preserved examples of their rotating discs so I have been working on the assumption that the Rhymney ones would have been similar.

I've just checked through all my Aus semaphore signal photos - many of which are McH originals and it would seem that I never saw one (because if I had I would have taken at least one photo of it!) 

[Darwinian]

This is one of the sources I’ve been looking through.

 

http://www.victorianrailways.net/signaling/discpage/discnew.html

[The Stationmaster]

22 hours ago, Darwinian said:

This is one of the sources I’ve been looking through.

 

http://www.victorianrailways.net/signaling/discpage/discnew.html

Alas I never found any of the old style although I got several photos of a later style used in Queensland but also found on a recreated heritage line in NSW - but they are very different and of no use to you for the era you're after.

[Darwinian]

It was actually just about warm enough (10 degrees Celsius) to venture into the shed this afternoon. After adding the safety cage and platform to the elevated rotating disc signal I decided it was time to tackle a rotating ground disc (Wizard MSE kit).

 

I drilled out the cast base unit to take the microbore tube and then drilled out clearance for a thick washer in the base. Tube of various telescopic sizes then produced this set of parts. The microbore tube is a sliding fit in the next size up tube under the baseplate and is held up by the washer inside the signal body.

 

 

The lamp case is drilled out (not very accurately from below, might have to do another) and fits onto the top of the microbore tube. When it's been painted a crank will be attached to this tube to allow a servo to rotate the signal.

A fibre optic filament can be be fed up into the lamp and will in due course terminate in an LED housing at the bottom of the microbore tube. So the signal will be able to rotate, be lit and there is no friction/wear on the fibre optic filament itself.

 

Here are the parts fitted together with an overlong fibre optic filament being illuminated by having the LED light on my phone held at the end.

 

[Darwinian]

Small parts painting day. Hit on the idea of using cocktail sticks to hold them and then stick them into an old eraser to dry.

 

 

While doing this I also looked at the etch for the discs/balance arms for the rotating ground signal and realised I should have attached the balance arm and its bracket before fitting the lamp holding ring to the top of the rotating tube. Doh!

 

While on the topic of the disc signals does anyone have any recommendations for attaching the disc to the lamp body. I was planning on soldering it on with 125 solder and then fitting a tiny disc of red lens material onto the front of the disc.

[Darwinian]

The Elevated rotating disc so far:

 

This hasn't worked. The elevated rotating disc linkage I have made only rotates the disc by 45 degrees when it needs to be 90 degrees.

 

 

Can any one suggest how I can gain the extra movement. The movement of the balance arm cannot be increased. Do I need to put an unequal crank on the post?

Here's the first attempt set up.

 

[Michael Hodgson]

The easiest way to get the desired amount of turn every time on a rotating disc is to mount it on its operating rod, but of course if it has to be offset from that then you're forced to have some sort of linkage such as you have there.   

 

I would think an unequal crank is your best solution there, but it coud still be difficult to get exactly the right amount of rotation.  If you put enough offset onto it to get a bit more than 90 degrees, you can reduce to the correct amount of travel by adjust a servo driving it.

[Darwinian]

Well an unequal crank has sorted the operational issue even if it isn't prototypical. I had hoped the fibre-optic could be bent around closer to the support bracket but this was the best I could do so I will paint it to look like part of the support for the lamp assembly.

 

 

 

[DLT]

Just discovered this topic, I have a somersault in the to-do list, so I will be studying.

Many thanks,

Dave.T

[Stephen Freeman]

Bending fibre optic cable can be done with limitations. A much sharper bend can be had with the application of heat in the form of an adjacent (but not touching) hot soldering iron, the greater the sacrificial length the sharper the bend, gravity is your friend here. However in this case I don't think a sharper bend would be sharp enough. Have you thought about a very small LED (0402 size) in the base of the lamp and fibre optic thereafter. The fine wires for the LED would be easier to bend and hide.

[Darwinian]

On 16/03/2023 at 23:25, DLT said:

Just discovered this topic, I have a somersault in the to-do list, so I will be studying.

Many thanks,

Dave.T

Thanks, don't hold your breath, these get worked on when I am in the right mood, they are very fiddly.

[Darwinian]

On 17/03/2023 at 13:33, Stephen Freeman said:

Bending fibre optic cable can be done with limitations. A much sharper bend can be had with the application of heat in the form of an adjacent (but not touching) hot soldering iron, the greater the sacrificial length the sharper the bend, gravity is your friend here. However in this case I don't think a sharper bend would be sharp enough. Have you thought about a very small LED (0402 size) in the base of the lamp and fibre optic thereafter. The fine wires for the LED would be easier to bend and hide.

The issue with these elevated discs is that the shaft the lamp is on has to rotate in the bracket mounting it to the post. Hence feeding fibre optic up through the shaft. Doesn't leave anywhere to mount an LED below and I'm not sure the leads would appreciate being repeatedly twisted through 90deg.

I know you and others prefer LEDs in the lamps but for me personally they look too bright. When I were a lad we had a semaphore distant signal at the end of the garden and my memory is that the lamp flame was invisible on all but the murkiest of days. So for me most of the time it will be a case of "I know the lamp is lit even if I cannot see it". Unless I turn the layout lighting off that is.

[Michael Hodgson]

2 hours ago, Darwinian said:

 

I know you and others prefer LEDs in the lamps but for me personally they look too bright. When I were a lad we had a semaphore distant signal at the end of the garden and my memory is that the lamp flame was invisible on all but the murkiest of days. So for me most of the time it will be a case of "I know the lamp is lit even if I cannot see it". Unless I turn the layout lighting off that is.

 

The mechanics of this signal are the difficult bit, brightness of an LED is much easier to fix.

Voltage = current x resistance (Ohms law)

Brightness depends on current, so if an LED is too bright, just increase  the value of resistor in its feed until you get your desired light level.

[Darwinian]

23 minutes ago, Michael Hodgson said:

 

The mechanics of this signal are the difficult bit, brightness of an LED is much easier to fix.

Voltage = current x resistance (Ohms law)

Brightness depends on current, so if an LED is too bright, just increase  the value of resistor in its feed until you get your desired light level.

True, but I've never really understood the characteristics of LEDs enough to know that I won't end up below the threshold current with the LED not illuminating. 

At the end of the day I just prefer using the fibre optics and having all the electrics below the baseboard. Personal preference (or laziness) on my part.

[The Stationmaster]

In real life the light from a properly trimmed and set signal lamp could normally only be seen when looking directly at the signal.  There was virtually no side light at all as it only came from the bulls eye lens in the lamp case and that could only  be seen from fairly close up.  And if the lamp was not properly trimmed or the wick had got dirty the light was even less visible, even from the correct viewing angle..

 

An LED might possibly be convenient but it would have to be reduced toa barely visible glimmer to be anything like approximating to the real thing and would have to be invisible from most viewing angles.  In fact in order to see it at all you'd really need a tv camera mounted at the front of a train.

[Stephen Freeman]

Controlling the brightness of a led isn't quite so simple as controlling the voltage. What is needed is a PWM device, MERG sell such a kit for such a purpose.

[bécasse]

Painting over the LED might be more effective than an electrical solution.

[Darwinian]

That's what I have done for tail lamps.

I've been working on a mark 2 version of the elevated disc. It's a lot less chunky and I've kept the working tolerances better so there is less slop.

[Darwinian]

Revised mechanism with lamp.

[KingEdwardII]

How did you make the unequal crank? Is it an etch or something you cut out of sheet brass?

 

Yours,  Mike.

[Darwinian]

3 hours ago, KingEdwardII said:

How did you make the unequal crank? Is it an etch or something you cut out of sheet brass?

 

Yours,  Mike.

It came from a Wizard models etch of signal fittings. I cut it down to just the two holes closest to the pivot.