DC on a DCC Layout

[DAVISinGP]

Well, the Power Terminal with Insulated Gap suggested by Yardmaster did the trick and is perfect for my current (pun intended) needs. My old trolley can now rest quietly on a siding.

I have a related question: what would I need to power the "dead" side when and if I want to extend the track a bit?

I have a Digital Commander set with an EZ-Command controller. I presume I will need another source of power for the "other side" that can easily be turned on and off. What would be an easy way to do that?

Thanks.

[Flare]

I would just wire up a DPDT switch to the 'other side'.

That would enable/disable power to both rails at the same time from your existing controller.

[DAVISinGP]

I would just wire up a DPDT switch to the 'other side'.

Sorry - very new to the hobby. Could you tell me what a DPDT switch is? Thanks.

[Flare]

Sorry - very new to the hobby. Could you tell me what a DPDT switch is? Thanks.

Sure.  Basically it's a toggle switch that controls two circuits at once.  Much cheaper than a second DCC controller and you won't have to worry about synchronizing them.

Leave one circuit unconnected and wire the other to the siding's rails and you can turn it off and on with the switch.


You can find a more detailed explanation on the different kinds of switches here:  https://learn.sparkfun.com/tutorials/switch-basics/poles-and-throws-open-and-closed

[Terry Toenges]

To add to what Flare said, the DPDT abbreviation means "double pole double throw".

[DAVISinGP]

Thanks guys.

I hate to act stupid, but in the case of electrical engineering, well, I am.  

If I connect a switch and wires to the "dead" section of track, where is the power coming from? Am I splicing into the existing wire from the controller to the track?

[Flare]

If I connect a switch and wires to the "dead" section of track, where is the power coming from? Am I splicing into the existing wire from the controller to the track?

That's one option.  Another would be to tap directly into the gapped track section since it has connectors underneath for both ends.

Just get a pair of Bachmann feeder wires and connect them to both ends of the gapped track with the switch between them.

[DAVISinGP]

Thanks again.

I was also thinking that perhaps I could pick up power from the other terminal track connector. I have an extra controller-to-track wire assembly - what do you think about utilizing that?

[Flare]

The other side of a terminal rerailer?  That will work too.

[DAVISinGP]

Thanks for all your help.

My education continues...

[Warflight]

All of this is great advice... I too have a few DC engines I run on my layout, and yes, I pull the engines off the track when not in use.

Lately, I've been making an effort, to put a decoder in each engine I can (obviously, it's not happening with the Gandy Dancers, or the DeWitt Clinton, or the John Bull, but the Norris engines have space in the tender, and the motors are already isolated, and it's just two wires to solder)

If your engine has an 8 pin plug (or if you're feeling squirrely enough to hard wire) I would suggest a simple (cheap) decoder for it... if you can.

Otherwise, if all you're doing is using it every so often, and taking it off the track, or putting it on an isolated track, you're still fine with it.

[DAVISinGP]

If I leave one line connected to the other side of the "split", can I use an SPST on the other lead, or is there some reason I should use the DPDT to both?

[Flare]

If I leave one line connected to the other side of the "split", can I use an SPST on the other lead, or is there some reason I should use the DPDT to both?

A SPST would work too, I suppose which switch you use is a matter of personal preference.

In my case I prefer not to have any power going to a segment that's supposed to be turned off.

[DAVISinGP]

...I prefer not to have any power going to a segment that's supposed to be turned off.

That makes sense.

[jward]

what you are doing with an on off switch  to control power to a section of track is a time tested concept that was used for many years before DCC came along. It is known as block control. Using only one rail to control the section via a single pole switch is also time tested, known as common rail wiring, where one rail acts as a common return to the power supply, similar to a grounded chassis in electronic equipment. Unless you have a special situation such as a reversing loop, there is no need to isolate both rails, or use a double pole switch. In your case, where you are merely killing power to a section of track, a SPST, or on-off switch will do just fine. Just be sure that the contacts can handle the current output of your power supply. In the case of EZ command, with a 1 amp output, a switch you can buy in Radio Shack with contacts rated 3 amps will be more than enough.

The concept here can also be applied as many times as you want on your layout. You could, for example, have every siding on your layout isolated, and park all your locomotives in their own track when not in use.