Isolating a siding

Put an insulating pin in the center rail at the beginning of the siding. Run the hot wire thru a simple on/ off toggle switch to the siding center rail.

Then you just need to add an insulating pin to the center rail to separate the siding.

For O-27 use 6-65041 Insulating Pins

For O use 6-65543 Insulating Pins

This one works for me...good luck with the project...!

You did not say, but if that MTH engine runs under DCS, you might have a problem when you turn track power back on for that track segment.  Search the forum for "MTH watch dog signal" and you should find the threads that discuss and solve the problem with some electrical equipment.

Chuck

The very first line in the OP’s post is,“I have a conventional layout with tubular track…”

None of this DCS information is pertinent to him. All he needs is an on/off switch.

Good point Rich, I just responded to the DCS post, I removed the extra info.

Paul the schematic for the Atlas switch shows a DC setup with the hot lead going to an outside, isolated rail.  For three rail AC I imagine you run that hot lead to an isolated center rail?

That's right coach, hot goes to the center rail, and I always insulate and ground the outside rail too...some say that's not needed, but it works for me. I should have clarified that...why Atlas still prints the diagram that way is a mystery, given the dominance of their 3 rail business...does anyway even use DC these days

Like others have described, you need to run a separate power feeder to the siding in question and isolate the siding from the mainline, yard ladder, or whatever by either cutting the rail or using an insulating pin in the connection between the center rails. The "hot" wire for the feeder to the siding should be routed through a SPST switch like this one. I'm using a bunch of these to toggle power on and off to individual whisker tracks coming off my turntable and they're working great so far.

Here's how I power my yard tracks, the lighted pushbuttons indicate power is applied to a specific track.  Having a power indication is a useful tool.

If I were doing conventional sidings again, I would definitely either have lighted switches or a light bulb that came on when power was applied. I would also insulate one of the outside rails on the last piece of track and hook that up to a illuminated bumper (would have to insulate a die cast bumper as well) or a light bulb on my control panel. That way I would have extra information when the train reaches the end of the siding (especially if you rearrange trains).

@CarGuyZM10 posted:

If I were doing conventional sidings again, I would definitely either have lighted switches or a light bulb that came on when power was applied.

What's a "conventional siding"?

Gents, per the discussion, track power for yard sidings (also conventional) is this gang box ok?  It says DC so it kinda threw me.  I'm going to have 6 sidings to park on so I need to isolate them.  

https://www.amazon.com/Nilight...B08G1M6C58&psc=1

https://www.amazon.com/dp/B08T...kle_lsi4d_asin_2_img

I looked at these also.  I like what John said about illumination to be sure for quick glance if a siding power is on before I have an accident.

Oh, one other thing when formulating your responses since you guys are so much more up on this than I, ...IF one day I upgrade from conventional to Legacy, will they still work with constant 18V power?   I would only want to built this once.   Hopefully.

Try this one for18v -- https://www.amazon.com/FXC-Roc...B0858X4SC2&psc=1

Most modern autos have 12 volt electrical systems while most large trucks have 24 volt systems.

I just installed an Atlas 24" turntable on my layout. Here are the SPST toggle switches I used to power on/off individual whisker tracks and an additional siding where I plan to store locomotives. With a 15A/250V rating, they're major overkill, but they're a good size, seem solidly built, and have a good tactile feel to them. If anyone is curious, I wired this DPDT momentary rocker switch to the turntable's 12V DC motor and it works great.

Here are the finished products - the panels are 3D printed

EDIT: I use Fastrack, so I use the lighted bumpers to indicate which tracks are powered on. Keeps the wiring simple

Does anyone know why using a switch that says it's for 12volt isn't a problem?   Isn't our systems up to 18 volts at full when running legacy?  I guess it could be 12 v at half speed or something.   Please explain what I"m missing.

Generally speaking, electronics that physically make and break circuits have two contact ratings, one for DC and one for AC. With AC, the voltage passes through zero in relation to the AC cycles mitigating any arcing that occurs when the contacts change state. However, with DC loads, the voltage does not cross a zero point and thus does not mitigate any arcing necessitating a lower DC rating over AC:

Here is an example that shows the differing AC and DC ratings:

When purchasing something like the Amazon item posted earlier, it is a purpose driven product and so to keep things simple, they say it is for nominal 12V (DC) that the vehicle operates at. (Note, the cars electrical system can approach 15VDC when running as the Alternator is charging the battery). Based on these electrical properties, it would be a pretty good wager that if one were to open up that product and reveal the model of the switches, and looking up their data sheet, you would find an AC rating in excess of 18VAC. The safest thing is to check the AC ratings. If none are listed, move on to a product that does.

Note: The above does not take into account illuminated components as they may require DC voltage for illumination. Some of these pull the power for illumination from the same switched circuit while others have provisions for auxiliary power for illumination.

OK, so does that mean this switch here will be safe to use for my sidings?  Figuring 18 volts constant if I upgrade to Legacy later.

https://www.amazon.com/dp/B08T...kle_lsi4d_asin_2_img

Why not use the ones that I showed you  earlier. They are identical to the first ones you mentioned except are rated at 24 volts instead of 12. They would be more than capable of handling the 18v. constant on the track.

Decided against the sealed box type.  Think I prefer individual switches, but I'm trying to learn what I can have 18V running through constant and still be completely safe.   I don't want things getting 'warm' under there.

I linked some above that meet that criteria. I'm using them to toggle track power on my Legacy/TMCC layout and no issues so far

Thanks Mike, (and all), I was just thinking options for the OP and myself.   Input always appreciated.

@bmoran4 posted:

Then you just need to add an insulating pin to the center rail to separate the siding.

For O-27 use 6-65041 Insulating Pins

For O use 6-65543 Insulating Pins

You can also use a Q-tip (cotton cut off on both ends) cut it to size and insert it. Or a thicker, round tooth pick. Or a very small, round wood dowel. Basically any non-conductive, small tubular item will work.

I've used these red lighted ones with success and, because I run a command layout at 18 volts and they're rated at 12 volts, I wire a simple diode in place so as not to burn out the led.

Amazon.com: 5pcs SPST LED Lighted Rocker Toggle Switch Linkstyle Marine Toggle Switch, On-Off LED Toggle Switch 12V 20A for Car RV Vehicles Truck Boat : Automotive

When you convert to DCS

be aware that when any track power is detected by the circuit in the engine, it will add time to the clock.

that’s why I isolate all 3 rails on my spurs

@1drummer posted:

When you convert to DCS

be aware that when any track power is detected by the circuit in the engine, it will add time to the clock.

that’s why I isolate all 3 rails on my spurs

I don't follow. What power is being detected when the center rail is isolated and disconnected (via an SPST switch in the "off" position)? I don't understand why the isolation of the outer rails makes any difference. Maybe there's something I'm missing here

@1drummer posted:

When you convert to DCS be aware that when any track power is detected by the circuit in the engine, it will add time to the clock.

that’s why I isolate all 3 rails on my spurs

If you disconnect the center rail, there is no power to the electronics.  I can assure you that the clock does NOT run in that condition or it would run on your shelf or in the box.

@gunrunnerjohn posted:

If you disconnect the center rail, there is no power to the electronics.  I can assure you that the clock does NOT run in that condition or it would run on your shelf or in the box.

Glad I'm not crazy

@Mike0289 posted:

Glad I'm not crazy

At least not 100%!