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Controlling 2 Traintech signals from one switch - is this possible?


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I'm at a point in my layout construction where I am starting to think about signalling.  It's an 80s BR Blue era shunting layout with trains arriving and departing via a single line from the off-scene main line. 

Trains in the arrival/departure 'kickback' siding can either return to the main line or take the diverging route of a turnout which leads to the yard reception siding. 

I am planning on having two signals  protecting this turnout: a 2-aspect colour light which allows access back to the main line; and a ground signal which allows access into the Yyard. 

Bearing in mind that both lights can be red at the same time, but only one can be green/white, could I use a single 3-pole centre-off switch to control these signals?  I am thinking the central position could be 'both red', switch up for 'clear to main' and switch down for 'clear to yard' ?

I realise that I could spend a couple of quid and just by two switches, but I seem to like making things difficult for myself on this layout build. 

Any advice would be appreciated. 

Thanks 

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Its simple with a two-pole (or greater) rotary switch.  Needs minimum of 3 positions. 

 

A 2-pole 6-way would do, you typically set a limit tab-washer on the shaft (supplied with switch) to set it to three positions only. 

 

Wired thus:

 

1415197749_Annotation2020-07-11113034.png.25f8c38b59ac7b0fad79e5c5afb6852f.png

 

It could be done with a centre-off switch, but the stuff behind it might get more complicated.  I can see how to do it with two relays controlled by the centre off switch, with one relay energised in each direction. 

 

 

 

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And with colour light signals it would not normally be a GPL in use but a subsidiary mounted on the main signal post and showing the white lights only, no red.

Rather than having a 3 way switch that allows you to set the wrong aspect why not use a normal two way switch and select the aspect by the point position, preventing mistakes?

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Thanks for the comprehensive information on the shunt signal.   I am quite partial to a feather signal but I suspect it would not be prototypically correct, bearing in mind the next 'signal' on the diverging route (if it were visible and not beyond the scenic break girder bridge ) would the red light on the buffer stop?

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1 hour ago, Suzie said:

You can get a type of double pole switch which is an ON-ON-ON type and this will do what you need. It is basically two 2-way switches where in the middle position one is one way and the other is the other way so they can both be on ant the same time.

 

Example switch here:-

https://uk.rs-online.com/web/p/toggle-switches/7347202/ 

 

Thanks. Believe it or not, I have a HND in Electrical and Electronic Engineering, but I got that over 30 years ago :o and have not had much need for it until I started building the layout about 18 months ago.  I will look into these switches.  Thanks again. 

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  • 4 weeks later...
Posted (edited)

It looks like I might only need a 'shunt ahead ' ground signal to do the job at the location in question. Extract from wiki below;

Screenshot_20200809-142914.png.cdffafb3c59a196c893720ff721d0678.png

 

In the picture below, my signal will be at the location illustrated by the piece of chalk. When it is set to danger (yellow and white) trains can pass it to enter the yard (where the 08 is standing). When it is clear  ( two whites) trains can leave to access the main line to the station ( occupied by the 25 in the photo).  I will have to assume that there is a further colour light signal at the junction with the main line. I was contemplating having a two aspect light with a feather into the yard but I think that may be over the top and the ground signal is more prototypical. 

 

20200809_142937.jpg.3181d8d430b95f8d780c90721b55a281.jpg

 

I will probably have another shunt ahead signal on the point from the yard access road show below (being used by the 08).  The signal will clear to allow trains to access the arrival/ departure road pictured above and be passable at danger to access the yard headshunt. 

20200809_144241.jpg.0d92f72453dc5dd9ee0e68bb6fd296d2.jpg

 

I will have to 'standard' ground signals. One each side of the point  at the entrance/ exit of the road to the fuelling point. 

I have purchased one such signal from Traintech and hope to install it in the next couple of days. 

Edited by 9C85
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The author of that wikipedia entry has got confused. A shunt ahead signal is a subsidiary on the post of a main signal and only shows two white lights, where we started several posts back. You can use a yellow shunt signal, as you indicate, where the signal is only cleared for moves over a crossover to the main line abd can be passed at danger fo moves within the sidings or headshunt. These are standard ground position light signals with the red lamps replaced by yellow. For the proceed indication they show two white lights at 45 degrees. For danger they show either two yellow or one white and one yellow arranged horizontally.

ie the older 3 lamp style has two white and one yellow lamp, the new 4 lamp style has two white and two yellow, updated 3 lamp units have a LED unit in the pivot lamp position that can show yellow or white.

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