Using two separate, center-off SPDTs (not DPDTs) for the south and north yards, how can I wire them so that the yards operate independently of each other - and independently of a separate mainline direction, center-off DPDT? Both yard tracks lead into one of these loops, separated by a manually-operated DCC-friendly Walthers/Shinohara turnout. My layout is DC.
That mainline DPDT controls the entire layout and, in conjunction with another DPDT, operates the double reverse loops. I understand I could probably use SPSTs, but SPDTs are what I have in quantity - and used successfully for two years to power a nearly identical yard configuration on a former layout - so no need to recommend them. The yard wiring I used on the old layout doesn't seem to want to work here! I tried attaching the PDF schematic to make it easier to visualize the layout and wiring configuration, but I kept getting an error message. I notified an administrator a few days ago and am awaiting a reply.
I gapped the north rail of each yard track between the end of turnout #10 that leads directly into the yards and the end of the yards. However, when I wired a switch's center lug to a gapped rail and one end lug to the power pack, I got only one-way polarity within the yard. To get two-way polarity within the yard, I also had to toggle the mainline direction DPDT - an extraneous motion I want to eliminate so that I only need to toggle a SPDT and be able to run locos into and out of the yards. My objective: to make each yard either "dead" or "alive" and electrically separate from the other - and separate from the mainline DPDT. How should I wire the two SPDTs to achieve this? Wire all three lugs or only two? To what? Gap more rails and/or add feeders? If so, where? Thanks for your help!
Kerry
The administrator is going to tell you that it is impossible to attach a pdf file. You can post a picture on someplace like Flickr or Imgur and share the link, but not Google or Facebook.
Don't you need the polarity of the yard to be the same as the mainline, to prevent a potential short?
I would think the center lug should get its power from the the North rail feeder or bus (outside the yard and gap) and then have another lug feed the yard North rail. The other lug would be bare, and the off position.
Henry
COB Potomac & Northern
Shenandoah Valley
you posted this on another forum ... and a .pdf file is not a graphics file (e.g. jpg, gif, png)
HOmainlineI gapped the north rail of each yard track between the end of turnout #10 that leads directly into the yards and the end of the yards. However, when I wired a switch's center lug to a gapped rail and one end lug to the power pack, I got only one-way polarity within the yard. To get two-way polarity within the yard, I also had to toggle the mainline direction DPDT
it sounds like the power pack terminals are connected to the rails thru a DPDT switch wired as a reversing switch. in one position, the DPDT reversing switch connects the positive (+) terminal of the power pack to the "north" rail and in the other position, it connects the (+) terminal to the "south" rail.
by connecting your yard switch directly to the power pack you bypassed the DPDT reversing switch. If you connected the yard switch to the (+) terminal and the "north" rail, there will be no power on the yard tracks when the DPDT reversing switch is in the position that connects the (+) terminal to the "south" rail. In this case, both yard rails are connected to (+).
you can do what BigDaddy suggests or connect the yard switch to the corresponding terminal of the DPDT reversing switch instead of the power pack.
HOmainlineMy objective: to make each yard either "dead" or "alive" and electrically separate from the other - and separate from the mainline DPDT.
you could use a single DPDT SPDT switch for both yards. Connect the center lug to the mainline DPDT reversing switch and the end lugs to each yard rail. The switch connects power to one yard or the other, or neither in the center-off position.
greg - Philadelphia & Reading / Reading
RR_MelConvert the PDF to a JPG and post it normally.
What is normal for us, is not normal for newbies. They can't just control C or paper clip a photo. There are further instructions on a sticky post in the general forum.
gregcou could use a single DPDT switch for both yards.
I thought about suggesting a DPDT switch off the power pack, but that would always have the potential for a short if not the same as the mainline.
DPDT center off switches cost less than a McDonald's latte, not Starbucks, Micky D, on ebay.
re: graphic files -- you also need to post them on some other server, i use imgur.com and provide a URL in the thread post.
in the meantime, i believe this is a link to his Great Northern Wiring Schematic
BigDaddy thought about suggesting a DPDT switch off the power pack, but that would always have the potential for a short if not the same as the mainline.
if my explanation is correct, there's a short when the metal wheels bridge the gap in the yard tracks when the reversing switch is in the position when the yard has no power.
he says he has SPDT switch in quantity. I corrected my comment above about using a single switch to control both yards.
Henry,
Thanks for the info about PDFs on this forum. I have no means of photographing anything, however.
How about if I send the PDF to your personal e-mail via the message feature here? Then you can take a close look at the track configuration and gapped rails, co-joined turnouts (nos. 8, 9 and 10 on the schematic) in the area of the yards etc.
The wire to the gapped rail must be connected to the center lug of the SPDT rather than to the bus or its feeder. My reverse loop DPDTs are so wired, and all my Kalmbach wiring books show it that way as well. I did try your method just to see and got zero current.
I sent you a pm with my email. I'd be happy to do it.
When you say "the gapped rail", is that inside the yard?
Greg,
You wrote in part:
"...you could use a single...SPDT switch for both yards. Connect the center lug to the mainline DPDT reversing switch and the end lugs to each yard rail. The switch connects power to one yard or the other, or neither in the center-off position."
This sounds good for getting one yard or the other to be "live." I'll give it a try. But it won't allow both yards to operate simultaneously, independent of the other, which is what worked just fine on the old layout and what I want to duplicate here.
Mel,
I have no idea how to do that conversion. I'm on Windows 10, which has an app called "Paint 3D." Same thing or something else?
HOmainlineThe wire to the gapped rail must be connected to the center lug of the SPDT rather than to the bus or its feeder.
if you're using your SPDT switches as simple SPST switches, it shouldn't matter whether the rail or power source is connected to the center lug, as long as one of them is.
the diagram below for a SPDT switch illustrates the internal connections of the switch. The "center lug" should refer to 1P in the diagram or the common terminal on the switch. The diagram illustrates that whatever is connected to 1P can be connected to 1T or 2T.
if you connect the power source to 1P, the one yard rail can be connected to 1T and the other yard terminal to 2T. In the center-off positon, 1P should be connected to neither 1T or 2T.
HOmainlineBut it won't allow both yards to operate simultaneously, independent of the other, which is what worked just fine on the old layout and what I want to duplicate here.
i assume you want to park a locomotive in a yard and use a different loco from the other yard. You would never want, nor need to have both yards powered at the same time.
sounds like eventually you might want a number of tracks to park locomotives on that can be powered off. Understanding the current problem will eventually help with that.
gregcif you're using your SPDT switches as simple SPST switches, it shouldn't matter whether the rail or power source is connected to the center lug, as long as one of them is.
I could be lost in the array of DPDT switches, but if the power pack stays the same, and Kerry is using the DPDT on the main to control direction, then it does make a difference what powers the SPDT.
Kerry on the right side of this page, click on your messages.
I have plenty of DPDTs, but I simply want to duplicate the wiring using the same two SPDTs (still happily situated on the fascia!) for the yards that I had for the identical yard configuration on an older layout that I tore down in January.
Those two SPDTs are still wired exactly as they were then, when everything worked perfectly (e.g., the yards operated - "live" or "dead" - independently of each other and of the rest of the layout). The only wires I disconnected in the transition were those soldered to the old yard tracks. Somehow, mysteriously, those SPDTs aren't doing the job they did before.
A thought: Since this new layout has two nearby turnouts (DCC-friendly nos. 8 and 9 on the schematic) directly connected to each other - and then no. 8 directly connected to no. 10 (which is manually operated and leads into the yards), I'm thinking that I may need to gap some other rails and/or add feeders in new places.
On the old layout, there was a sectional track or two of separation between turnouts no. 8 and 9. Could this be the difficulty now? If it's relevant, turnout no. 8 leads into one of the reverse loops.
Your thoughts?
BigDaddybut if the power pack stays the same, and Kerry is using the DPDT on the main to control direction, then it does make a difference what powers the SPDT.
i said "power source" to differentiate it from the gap'd rail in the yard. It could be the mainline rail, the appropriate terminal on the mainline DPDT reversing switch or some other connection.
In the corrected version of your first post, you wrote (italics mine):
Sounds promising - for single-yard only operation. I'll give it a shot.
This is similar to another potential solution I tried when I first took this problem to a knowledgeable modeler (who helped set up my original yard wiring on the old layout in 2016) here in town a few days ago.
He suggested wiring the SPDT's center lug to the gapped yard rail + one end lug to the center lug of the reverse loop's DPDT + the other end lug to the relevant (negative in this case) track power bus. That's when I got loco movement in one direction only (single polarity) within the yard and had to toggle the mainline direction DPDT - and the SPDT - to achieve dual polarity/forwad and backward loco movement.
His suggestion also included connecting the center lugs of the two SPDTs to each other + one end lug of the second SPDT to a gapped rail of one yard + the other end lug to the gapped rail of the other yard. I never got that far.
Stay tuned. And thanks for your suggestions.
I dunno, sounds like talking over it enough times is making it way more difficult than it sounds.
If the power pack connect to a DPDT reversing switch, which connect to the main line, then simply tap off the yard power BEFORE the DPDT switch if you dooon;t want the DPDT to change direction in the yard. But changing the direction on the power pack will change direction on both the yard and the main (unless you also flip the DPDT).
If you want the yards to have independent DIRECTIOON control then you MUST gap both rails going to the yard and wire up another DPDT just like the one for the main line, supplying power from the power pack with the output connections powering the yard. Then you can reverse the direction of a yard train without affecting the mainline train. However, since there's only one power pack - there is absolutely no wy to have real indpendent control What you need are at least two power packs, and several SPDT toggles to connect power pack A or power pack B to a given part of the layout. Basic cab control with common rail wiring, which is what you see in every Atlas plan book.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks! I noticed your message. I'll read it and send you the PDF soon.
Yep. The north (inside) rail of each yard is gapped within each yard. The plastic rail joiner forming the gap is directly connected to the manually-operated turnout no. 10 in the schematic.
See my related reply to Greg elsewhere, where I suggested the possible need for more gaps and/or feeders. Yor thoughts?
Yep. It's a small (5' x 7') layout, so only a modicum of room for yards. They're adjacent to the freight depot and either - or both - will be used to store a loco plus three or four cars not in use.
Good point. I'm not planning on powering both yards at the same time. I'd just like to have them operate independently - each with a dedicated SPDT - as they did on the old layout. Then again, if just one DPDT can do the job, I'd be satisfied.
On the north side of the layout are what I call a mainline/north siding track and a south siding track, each of which can be powered on or off with its own dedicated SPDT. The actual mainline runs north of both.
If you'd like to see the PDF with the track and wiring schematic, send me a PM with your personal e-mail and I'll send it along.
Who's a newbie, Henry?! I'm just gleefully ignorant of too much techy stuff!
HOmainline Mel, I have no idea how to do that conversion. I'm on Windows 10, which has an app called "Paint 3D." Same thing or something else?
please read Model Railroad Wiring. i think it will explain why you've been told to connect the gap'd rail to the center terminal of an SPDT switch, possibly anticipating the use of a 2nd throttle.
Well, I did just that with what I have - "Paint 3D" - but the resulting schematic is distorted into an oblong shape and the critical part with the yards is only partially shown.
I saw no way to manipulate the shape or expand the frame's borders and increasing the percentage of the diagram shown did nothing to change that.
Much more effective, if you'd like to view and comment on the schematic, is to send me a PM with your e-mail, and I'll send it off to you as a PDF.
HOmainlineWho's a newbie, Henry?! I'm just gleefully ignorant of too much techy stuff! Wink
Newbie to the ways of this forum, doesn't say anything about your model railroad experience nor even your tech experience. Certain functions on this forum are just weird.
Here it is. The bottom of the pdf is cut off as it was sent to me. Not sure that makes a big difference for the question being asked.
Thanks, Greg. I'll do that. I've also been reviewing the other Kalmbach wiring books I have. They all show the center lug wired to one track or another, usually in reference to two-cab operation.
My small layout, though, needs and operates on just one power pack. I use a second one to run the Tortioses.
Super! And, nope, the cut-off portion is irrelevant. The focus is on turnout nos. 8, 9 and 10 on the right side and the south and north yards near the bottom. Turnout no. 10 is manual.
Note that the hand-drawn green and turquoise lines with the arrows pointing south to the control panel indicate the double reverse loop wiring.
Again, are the inter-connectedness and proximity of those three turnouts to each other at all important in determining just what wiring configuration I need so those two SPDTs do what I want them to do (and as they did on the old layout)?
If you have more than one way to get intot he yard area, then EACH needs to have an insulated joiner, otherwise the power will still come in from the main no matter what you do with flipping the SPDT. That's probbaly the only actual issue you are having. Whichever rail gets power from the SPDT int he yard has to be insulated at EVERY connection to the main to keep the power out and only controlled by the SPDT.
[quote user="rrinker"]
Randy,
Did you see the PDF schematic posted above by Henry? There is only one way to enter and exit the yards. And in each yard, only one rail (the outside or north) is gapped.
Look over the schematic closely and let me know what you think. Would you like me to send that PDF to you via a personal e-mail. If so, send me a PM.
The yards are part of the reversing loop?