Turntable Pit Rail Wiring In DCC System, Neutral Vs. Hot

Model Railroader Electronics and DCC
1

I’m at sea with electrics, so please bear with my terminology.

I have a DCC system and am about to wire a turntable. Does it matter which half of the pit rail I wire Neutral (black feeder) and which half I wire hot (red feeder)? Logic (inexperience?) tells me “no,” but I don’t want to blow my system.

Similarly, should I coordinate how I wire the reversing sections through the auto-reverser in any way?

Thanks.

Rick Krall

2

Which make and model turntable are you planning to use? Some have the auto-reverse circuitry built in, and some do not.

3

We need to know the brand and more specifics about the turntable. A rather cheap Atlas turntable is already wired to automatically reverse the polarity of the bridge rails as it rotates beyond a certain point as explained in the instructions that come with it; other brands may not have this feature and DCC auto-reverse module such as a Digitrax AR1 will handle the polarity issue.

4

Learn something every day…

It’s a CMR turtable, which doesn’t have auto-reversing circuitry. The manual advises wiring the reversing sections ((2) 4" sections) to maintain continuity of power and sound.

Rick Krall

5

Learn something every day…

It’s a CMR turtable, which doesn’t have auto-reversing circuitry. The manual advises wiring the reversing sections ((2) 4" sections) to maintain continuity of power and sound.

Rick Krall

6

Be advised, dcc on the rails does not have neutral or hot. it is AC, both are hot.

Rich

7

Noted, Rich, thanks. I was trying to distinguish between the red and black feeders.

In a nutshell, my question is this: Does it matter which of the pit rails I feed with the red and which I feed with the black? Same question for the reversing rails. Unlike sections of the mainline or sidings, I’m guessing “no,” but I want to be sure.

Rick Krall

8

If you are planning to use an auto-reverser, then the answer is simple - it doesn’t matter how you wire the turntable bridge rails. The auto-reverser will handle it. If you aren’t going to use an auto-reverser, then you will need a double-pole, double-throw toggle switch to manually change the polarity as necessary.

I would try to wire the lead tracks from the main line the same as the stall tracks directly opposite them, if there are any. This will allow you to run completely across the turntable with, for example, a consist with a dummy engine, or a steamer which is actually longer than the turntable bridge itself.

9

Exactly what I need, guys; thanks.

Rick Krall

10

Good luck on the TT btw. I have a couple of the CMRs and love 'em. Easy to connect for reversing polarity (I use an AR-1 for mine).