McKenzie & Holland Ground Signals

andrewnummelin
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McKenzie & Holland Ground Signals

Postby andrewnummelin » Mon Jan 07, 2013 5:56 pm

Following advice on this Forum about the use of servos for signal control, I started work on a set of 4 ground signals. I had cobbled together the first one when Mark Tatlow published information on his superb signal models including a rotating McKenzie & Holland ground disc (putting my efforts to shame).
http://www.scalefour.org/forum/viewtopic.php?f=9&t=1345&p=20803&hilit=highland+miscellany#p20680

It appears however that neither of us know how the prototype converted, within its base, the horizontal movement of signal wire or rod to rotational motion of the lamp. Does anyone here have any information on just how these signals worked? For the next bit of my layout I need another pair of these little things and I'd like to do better than with the first one!

Should I ever manage to extend the layout I'll need to make a set of these signals that were mounted on a post (3 or 4 above each other) and these must have been operated slightly differently. An example of a post mounted "ground signal" is illustrated below (from the Railway Magazine, January 1910, in the illustrated interview with Mr Prosser, the general manager of the Rhymney Railway): any prototype information, or modelling help, would be much appreciated.
rr.jpg
Regards,

Andrew Nummelin

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grovenor-2685
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Re: McKenzie & Holland Ground Signals

Postby grovenor-2685 » Mon Jan 07, 2013 7:25 pm

I'll need to make a set of these signals that were mounted on a post (3 or 4 above each other)

Your picture shows clearly enough how the post mounted version works, there would be no problem mounting several of these on a post, each having its own bracket.
It would be different with ground mounted signals as it would not be practical to have a vertical stack as that would need concentric shafts passing right through the lower lamps, they could be mounted side by side or one behind the other with the ones at the rear having extended shafts.

I don't have a drawing or picture of the specific style you and Mark are discussing but conceptually they are simple enough. The visible balance weight is fitted on one arm of a crank the other arm being vertical within or alongside the base, the signal wire will connect to the bottom of the vertical arm so pulling on the wire raises the weight. The vertical shaft holding the lamp and targets will have a lever arm projecting horizontally to engage with the vertical crank arm such that movement of the crank will rotate the shaft. Lots of ways of arranging that with or without an intermediate link bar so you do need to see an example or a drawing to be sure.

I have found a drawing of another version, similar in principle, which I will post when I have scanned it.
Regards
Keith

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grovenor-2685
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Re: McKenzie & Holland Ground Signals

Postby grovenor-2685 » Mon Jan 07, 2013 7:39 pm

Scanned drawing attached.
Regards
Keith
Ground-disc.PNG

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Mark Tatlow
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Re: McKenzie & Holland Ground Signals

Postby Mark Tatlow » Mon Jan 07, 2013 8:19 pm

Andrew,

I am sure you won't miss it but I have just found the relevent sections of the M&H Catelogue. I have plonked them on my Miscellany thread.

I do like that ground signal on a bracket. I am not sure I am allowed to have one for my Highland stuff, but I do like the idea!
Mark Tatlow

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David B
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Re: McKenzie & Holland Ground Signals

Postby David B » Mon Jan 07, 2013 10:30 pm

Andrew asked 'how the prototype converted, within its base, the horizontal movement of signal wire or rod to rotational motion of the lamp.'

I have scanned the attached from Raynar Wilson's book on Mechanical Railway Signalling (1909, p71). I wonder if it might help. This is a Midland signal,though whether M & H had any hand in it I don't know.

David

Midland-ground.jpg

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Noel
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Re: McKenzie & Holland Ground Signals

Postby Noel » Tue Jan 08, 2013 11:18 am

Andrew, are you aware of the drawing in WRA vol. V no.5 [May 2012] page 114?

Noel
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Noel

andrewnummelin
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Re: McKenzie & Holland Ground Signals

Postby andrewnummelin » Thu Jan 10, 2013 7:55 pm

Gents,
Thanks for all the information that has really prodded me to get to work!
Regards,

Andrew Nummelin

andrewnummelin
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Re: McKenzie & Holland Ground Signals

Postby andrewnummelin » Thu Jan 10, 2013 8:03 pm

Noel wrote:Andrew, are you aware of the drawing in WRA vol. V no.5 [May 2012] page 114?

Noel


Noel,
How could I have forgotten this? (Now that's a question that I trust will not elicit a sensible response!)
The drawing indeed shows the rather clever "crank" that makes the lamp rotate and also appears to restrain the lamp when either "on" or "off". Should be great fun to try to make one of these.
Regards,

Andrew Nummelin


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