Hi,
I'm still finishing out the backdrop on the new layout, and also finalizing the wiring schematic. The HO layout is 11x15 and fills the room, and has a lower level staging/storage area. The DCC system is Digitrax with two 5 amp boosters run thru two DCC Specialties 4 circuit breaker systems to give a total of power districts.
My first question concerns the "best" way to split the power districts for the two main lines. They are basically a double track configuration that goes around the perimeter of the layout. I am unsure whether it is best to have each main be a separate power district - or - have the two mains split so that the south half of the two mains is one district and the north half is the other district. Note that I typically run ABBA all units powered consists.
My second question is the best way to power on/off switches for terminal tracks. After a lot of Forum input, I decided that it would be a good idea to isolate some of the terminal & staging tracks so that the locos (especially those with sound) wouldn't be "on" all the time. Sooo, in example, do you wire the track feeders thru the on/off toggle switch, and assuming that's the case, do you run just one thru a spst or both of them thru a dpst, or ??? And, if the track has multiple feeders, I "assume" you would have to run all of them thru the same toggle switch. Is that a valid assumption? Of course the tracks in question will have plastic rail joiners to isolate both rails.
Thanks for your time - and advice. Obviously I am trying real hard to do this right the first time, and I would rather show my ignorance and/or uncertainty rather than screw it up.
ENJOY,
Mobilman44
ENJOY !
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
On our old club layout, we had reused the DC blocks. Each of the double track mains had 4 blocks, so each block got hooked up to one output of a PM42. We made it so that each main had its own booster. The yard was on the other side from where the main power feed was. Eventually we got another booster to run that side of the layout, as the bus wires were over 50' plus running through plugs every 6 feet or so. On that side we used one output for the yard, one for the lower side mains, and one for the upper side mains. So you could do it either way. What we did worked fine for our mostly display running, as a defect only shut down a small area, rather than the whole layout.
As for the shutoff tracks, I would go for the DPST switches. The output from each switch would then hook up to the bus wire for that track, just like DC wiring.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
The 'best' way to set up power districts will also have to take into consideration you operation scheme. If you run an approximately equal number of trains on both mains, you will probably want to break it up that way. if the one line gets light use and the other is heavily used, you might want to break the layout up into left and right sides, or something along those lines. Each power district has to have enough power to run what you plan to have on it at any given time. It does no good to set up a circuit breaker to trip a 1 amp and then try to run multiple sound units through it - the breaker would probably trip under normal operation. The more important consideration with the breakers is what stops when a short happens. The idea is to keep the operator way out on the logging branch from having his train stop when some some dope (usually the layout owner - ever notice how we build them but then make the most operating mistakes?) runs an open switch to the wash racks and shorts out the engine terminal.
As for shutoff toggles - I like turning off BOTH rails, not just one, so DPDT. All you REALLY need is DPST but they aren't as common and sometimes cost MORE than DPDT. And yes, if the track being controlled has multiple feeders, all the feeders have to go via the switch - just us a mini bus - oen pair of wires from the switch to the layout area where the track is, and attach all feeders for that track section to this set of wires. The wire generally does not ahev to be as heavy as the main power bus, since typically each track section being toggled on and off would only have one set of power on it. The voltage drop is related both to the wire size and length AND the amount of current being drawn, so there's little point in runnign #12 wire to feed a track which will hold one locomotive.
Oh and if you want indications for those toggles - get a bicolor LED and a 1-1.2K resistor and put it across the wires heading to the track. Then when you turn on the power to that track section the LED will light up.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
mobilman44 Hi, I'm still finishing out the backdrop on the new layout, and also finalizing the wiring schematic. The HO layout is 11x15 and fills the room, and has a lower level staging/storage area. The DCC system is Digitrax with two 5 amp boosters run thru two DCC Specialties 4 circuit breaker systems to give a total of power districts. My first question concerns the "best" way to split the power districts for the two main lines. They are basically a double track configuration that goes around the perimeter of the layout. I am unsure whether it is best to have each main be a separate power district - or - have the two mains split so that the south half of the two mains is one district and the north half is the other district. Note that I typically run ABBA all units powered consists. My second question is the best way to power on/off switches for terminal tracks. After a lot of Forum input, I decided that it would be a good idea to isolate some of the terminal & staging tracks so that the locos (especially those with sound) wouldn't be "on" all the time. Sooo, in example, do you wire the track feeders thru the on/off toggle switch, and assuming that's the case, do you run just one thru a spst or both of them thru a dpst, or ??? And, if the track has multiple feeders, I "assume" you would have to run all of them thru the same toggle switch. Is that a valid assumption? Of course the tracks in question will have plastic rail joiners to isolate both rails. Thanks for your time - and advice. Obviously I am trying real hard to do this right the first time, and I would rather show my ignorance and/or uncertainty rather than screw it up. ENJOY, Mobilman44
My layout is of similar size and design. I split mine with the north/south concept but Randy's point about how you operate is very valid. If you do it just right you can run a separate bus under each main and then connect them together at the breaker. Then if you ever need to split them apart for more power, no major rewiring is involved. Another advantage of the north/south split is shorter bus runs.
I too use DPDT switches on each breaker output. I come off the output of each breaker, run it through a DPDT switch on my control panel and then onto the power district bus, which is terminated on european style barrier blocks. The feeders then run off the bus wires. Nothing stops you from running multiple bus wires and then terminate them together on the breaker output (as described above). As long as each section is gapped you can easily move them to another breaker and/or booster in the future.
Engineer Jeff NS Nut Visit my layout at: http://www.thebinks.com/trains/
For the terminal tracks there is no need to complicate things by hooking up both rails to the on/off switch, no advantage is gained by doing this, just more wire and more work!
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums