Re: What is a "throat controlled relay"


Could you be talking about automating a reverse loop or using occupancy to throw an approached switch.

At my club (Crossroads Rail Road Club, Vandalia, Ohio), i automated two switches (Tortoise) one at the end of a single track reverse loop and one at the end of a double main to a single track through a yard. The project started with a purchased timer relay that is activated with a DIY light detector and a DPDT relay to throw the switches restart the timer every time a gap between cars passes over the light sensor and an additional 30 seconds after the train passes. 

Since i built the circuit i have found light detectors and relay modules for cheap on line making DIY unnecessary. These module could be put in configurations that automate your imagination or just throw a switch when it is approached.


On Sunday, April 11, 2021, 09:35:13 AM EDT, Don Vollrath <donevol43@...> wrote:

A throat controlled relay is  a DPDT relay used to set the polarity of the reversing loop based on the position of a turnout or “throat “ to following tracks. The fast acting  relay takes the place of a sometimes finicky (and expensive) AR controller. 
You provide the relay. You figure out how to selectively turn it on/off depending on the position of the throw bar of the turnout. 
Allan shows how to do this on his website using a 12Vdc relay and a diode with the relay coil wired from a Tortoise or other stall type reversible   turnout motor. The relay provides a fast polarity switch and greater amp capacity than other ‘slide switch’ mechanisms. 


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