Turnouts & Switch Machines

By Ty’s Model Railroad - 9/15/2010 09:58:00 PM

Atlas turnouts showing switch points

I have now installed four new Atlas under-table switch machines, one Atlas trackside switch machine, and a new motor for my Atlas turn table. I have also been collecting the various parts and components for the control panel that I am designing. I still need four Atlas snap-relays as well as the dual cab MRC controller I’ve had my eye on. I will have more details on this when I get a more finalized plan on its design. 

Atlas turnouts showing switch points

The under-table switch machines installed pretty easily, with only a few adjustments needed. The hardest part was keeping them positioned while screwing them in. A partner definitely helps with this step. One issue that did need some attention was the ease of movement of the turnout itself. The switch machine motors themselves are pretty powerful, especially with a 16V AC burst of power. However, the issue comes from the very small distance of the switch machine's movement as well as the slight flexibility of the plastic pin that attaches to the track switch point. 

Atlas under table switch machines with wiring installed below wooden benchwork

The switch machine's movement is just barely longer than the distance of the turnout point itself. This means that there is very little room for error when installing the switch machine as it needs to be installed perfectly centered with the turnout. Also, because the small pin that moves the switch point has a bit of flex, ANY resistance in the track switch point will prevent it from fully engaging. Because of this, I ended up having to remove the roadbed under the sliding bar of the turnout to ensure there was no resistance. After a few adjustments, the track turnout moved much more easily and everything worked fine. 

Atlas under table switch machines with wiring installed below wooden benchwork

As for the wiring, each switch machine will be on an independent Atlas switch controller; green wire being for the main line and yellow being for the turnout. All are grounded by a common wire which is the center brown wire. Switches 2 and 3, which branches from the main line to the front spur, are on a common switch and operate in unison as they will always need to be switched together when crossing off of or onto the main line. 

Atlas trackside switch machine installed beside an Atlas turnout on a model railroad layout

Unfortunately, I was not able to install an under-table switch machine to the turnout to my turn table. Because of this, I had to use a trackside switch machine. I wired it just as I did with the under table switch machines and attached it to the same brown common lead. I will have to find some way to hide this machine in the future. I have also attached my new turn table motor. It works great, but is a little loud. Hopefully this will be quieted slightly when the cover is attached. With that, there is where I am this rainy Wednesday evening. 

A motor installed on an Atlas turn table without motor cover


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