Wednesday, August 4, 2010

Working Lower Quadrant Signals

I have been asked in a comment on my last post if the signals are made to work and if so, do I intend making them work, the answer is yes on both counts.

I have had two signals working for about 6 years now and thought it was about time I pushed the signalling along.
I received the two brackets and two home signals last Friday night and have just started to work out their exact locations on the layout, hence the picture in the last post.
To make them operate I use cheap relays with a fine phosphor bronze wire soldered onto the 'clapper'? (the moving piece) the other end of wire is threaded into a hole in the bell crank arrangement to operate the signal. I also use a small weight on the crank to make the signal fail safe, i.e. a loss of power brings the signal to stop.
Now, you can use bell cranks available from model aricraft hobby shops that are quite cheap but I use the Circuitron Actuator (Part 800-8101) that is actually made to do just this job, although when I first bought them about 6 years ago I didn't realise that is what they were for.
I get them from the Model Railroad Craftsman at Blacktown and here is a picture from the Circuitron product catalog:

The actuator comes with 450mm (18") of wire in tube as shown above that would help with placement of the Tortoise motor if you are rich enough to use them for this.
The bell crank has limits placed on it's movement (adjustable with the two small screws) so that the stress is taken by the bell crank and not by the signal mechanism.
I will be mounting the signals on a piece of 3mm MDF and will set up the bell crank and signal connecting rod on it as well. I will lower the bell crank part through a suitably sized hole cut in the board and fit the relay underneath after. The relay positioning is easy as the phosphor bronze wire is about 100mm (4") long and has a lot of flexibility, it also takes up the excess movement at the bell crank.
I have previously installed the board under the layout by putting the signal up through a hole in the layout baseboard as this allows the signal, bell crank and relay to be set up and working but at the expense of having to fill the hole through the baseboard and around the signal. Does that make sense?


Simple enough really.

2 comments:

railmod said...

Thanks for the info Ray, I'll bear the Ciruitron Actuator in mind when I install a couple of Ian Millard's signal kits I have, Like your installation ideas - sounds like a good way to go.

Cheers Alex...

The Nimmitabel Extension said...

Thanks for the update, I have a few Ian Millard built lower quad signals and was toying with how will I get these to work.
I like the green button idea, it gives the feel and adds to the overall operation. Great work. Darren