I want to isolate a siding in DCC. Can I do this by placing a SPAT switch on one of the two bus leads to that siding or do I need to use a DPST on each of teh leads?
RicZ
A single switch (SPST) will cut the power to the prime mover, but I do not know what it will or will not do to the DCC system.
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Yes, cutting one side of the power feed still works in DCC, A complete ciruit is a complete circuit, break one side and things don't get power.
The only palce where there's a real difference between DC and DCC is between sections of layout powered by different boosters. You should not use common rail wiring as was common with DC (like using the Atlas wiring components - but even in my DC days I never did this, I always ran both sides and gapped both rails). With DCC and common rail, any voltage difference between the two sections when crossing the gap can appear across the decoder, in the worst case the two boosters are out of phase and you get double track voltage across the decoder, unless there is a common reference between the boosters. It CAN be done if the control bus between the boosters is optically isolated, and thus not electrically connected from booster to booster, but it is best just to avoid any potential issues and gap both rails.
For a siding to be turned off, one gap and a SPST switch works just as well as it did with DC. However, if you want to isolate a siding to be the program track, it must be gapped on both rails and all power feed (meaning double pole switch) must be shut off to prevent damage to the command station. Best is to not have a drive on/drive off program track, second best is to actually use a 4 pole switch and put a dead section longer than your longest loco between the main and program sections, that way if a loco creeps across the gaps it won't be bridging the program track to the main track power, resultign in either damage to the command station or the programming of every loco on the track.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
On the Route of the Broadway Lion, the left rail is common and it is a HARD GROUND to the building system: no stray current there. On the right rail + is forward and - is reverse. But of course subway trains do not back up and so there is no reverse on my layout.
Can a DCC signal work on just on rail?
ROAR
No, DCC needs 2 rails. Or a rail and an overhead, or a rail and an outside third rail. Just liek DC, you need a complete circuit for the power to flow. It's just a square wave AC. It won;t work with just one conductor any more than a lamp will light if you cut one of the two wires in the cord.
Hi!
I isolated 4 sections of my HO DCC layout, mainly to assure locos in the engine facilities and staging/storage areas were shut down when not needed. I know that a single pole switch will work just fine, but it was just no big deal to hook up a double pole switch, which is what I did. Of course the fact that I had DP switches on hand made the decision much easier.
I believe either type will do the job, but I - always a believer in overkill - feel the DP was the best choice.
ENJOY !
Mobilman44
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
Why not creat a siding with a power routed turnout .... when the turnout is set to the main the siding is isolated from the layout .... if it has a seperate feeder .. it would be, in essence, a progrraming track. True?