As promised, the track power wiring for the automatic wye:
OK, it works like this:
The wye is a junction between two mainline blocks, lets call them east (on the right), and west (on the left).
Your train is in the east block, headed west toward the wye. If the route is set straight thru on the main, route B-C, and the west block is set to your throttle/train, you proceed thru.
Your train is in the east block, headed west, and now the wye route is set for the wye leg from your direction, route A-C. Your train has power into the wye leg.
After your train is in the wye leg, you change the route to A-B, and you want to reverse your train and back out onto the main.
BUT, your train will still be moving WEST. So you do NOT reverse your throttle direction switch, you simply align the route to A-B, this will effectively reverse the polarity to the train. Your train will now back out on to the mainline still proceeding west, but now in reverse.
After you clear the wye, and set the route back to the main, you could now reverse your direction switch to proceed east, back the way you came.
Other features:
When the route is set to B-C, the rest of the wye is dead, a train or loco can be parked there.
When the route is set to A-B or A-C, the trackage between B-C is dead, preventing a train from the other direction from running the fouled turnout.
There you have it, complete control of a DC wye with only three push buttons.
Remember, with DC, direction is absolute, you are setting the track - EAST or WEST - it has nothing to do with the front or back of the locomotive.
If you use 4PDT relays like I do, there will be enough relay contacts for both the control and track circuits, but you will need repeater relays to drive the switch machines, unless you use the switch machine contacts for the track power.
Again, I only use the switch machine contacts to power frogs. And I need the addtional contacts of the repeaters for the signal circuits.
So the wye becomes one of the more relay intense situations, most others only require one relay per turnout for track power, control logic, and signal logic.
Sheldon
ATLANTIC CENTRALThere you have it, complete control of a DC wye with only three push buttons.
Not a big model railroader, just a switching layout at the moment, but my dad started me with a 4x8 plywood central in 1958. I have been following the DC DCC debate here for a year and have gotten some recommendations from Sheldon on sources to read about re the advanced DC control systems that have been developed over 70 years or so. Linn Wescott, a very bright and resourceful model railroader and part of MR for years desigined his version of DC "route control" and that story ran in 1957, in MR, starting with the May Issue I believe. It is amazing looking back at the history of this stuff, just how good a thinker the men from long ago were, to develop stuff like this. The articles are fascinating and easy to follow, if you understand how basic electricity works.
Many men developed these systems that were constantly improved over many decades. Ed Ravenscroft was a genius and inspired Sheldon. I have read his pieces also and some tremendous thinking went into that too.
Another model railroad electrical genius was Paul Mallery, reading also recommended by Sheldon. Paul was a Bell Telephone engineer that developed many useful things for the telephone company and holds numerous US patents on those. He has written several handbooks on basic electricity for model railroaders. I have the first edition of his 1955 hardcover book, the latest versions of his handbook for model railroaders along with older versions of those books. He was deeply involved in developing transistors so has seen all sides of the model railroad world one could say.
Re the topic at hand he developed a wiring diagram for a wye, with the north leg being a "stub" used just for turning an engine or train, using only one button to operate the wye turnout at the appropriate time. He made it an "X" section as Sheldon has mentioned. I have a diagram of that and will post it if I can figure out how to do so.
The saddest thing is, as Sheldon said here a ways back is to see advanced DC model railroad control systems dismissed as "flipping toggles" as if there is something wrong with that. In 1954 a real train approached a complex interlocking. The turnouts were set to describe a particular route through all of that trackwork. The engineer opened the throttle and just followed that route. On a layout like Sheldon has described, a few buttons are used to set up a route, on his layout, the power is directed to that route, and the train follows it too, just as realistic as the full sized version does. The old timers in this field had more practical knowledge of electricity than most model railroaders of today I suspect. Before you could buy it off the shelf...you had to figure out what you needed and build it yourself. There is a vast amount of PRIDE involved in that. We can learn plenty from the past, of this hobby, if we want to study it! I have nothing but the utmost amiration for the men who proceeded us of today, some of whom were real geniuses in their own right. Advanced DC control systems have a long and good history and are still practical today for those who enjoy that kind of work.
RHM
ATLANTIC CENTRAL As promised, the track power wiring for the automatic wye:
BNSF UP and others modelerHe wants to know how to wire a wye in DC. He is working in N scale. He can't find anything helpful, and I cant really either.
sheldon
i understand that this is how you wired your wye, that you understand and are comfortable with relay circuits and know where to get them cheaply. I see, because of the 3 relays and the extra gaps, that this circuit can unpower each branch of the wye. But i think this is overkill for a conventional wye as the OP asked about.
for a conventional wye, where the track above A is a stub long enough for a locomotive so that it can be turned, i see no need for the B & C relays. The connections to the uncommon contacts on relay A can be directly to the mainline tracks which you identified as blue and red. And there is no need for the isolation gaps between B & C.
The coloring of the connections between the A stub and common contacts of relay A depends on the position of the relay and would be opposite for the A-C route. Not sure if this is clear to the OP
i'm not sure, but i believe there is no need to power route the frog (if it needs to be), it's always connected to the bottom, red rail of the mainline track.
there is no need for relay A if the tortoise switch contacts are used. If a tortoise is not used, then relay A could be controlled along with turnouts A, B and C using the same switches (discussed previously) to select the route. If a pushuttons are used to control the turnouts, relay A needs to be latching, either a latching relay or a 4pdt relay with a holding circuit. of course, a simple DPDT switch wired as a reversing switch and used to manually control the reversing section polarity.
i don't understand why Randy suggested that the tortoise contacts shouldn't be used to switch the power to the A stub but is ok for the frog. The tortoise auxilliary switches are rated for 1A.
there a several options for wiring a wye. i don't know which is best for the OP. It would be useful for the OP to understand the tradeoffs.
i've learned a lot from this thread. having a good understand of things like this before doing them minimizes the effort, cost and potential rework.
greg - Philadelphia & Reading / Reading
Greg,
A few points.
First, we have no idea what the OP's real requirements are, he never responded to my offer to post this info, and has not responed at all since my posts begain. It was a different poster, stevetx, who requested I post this.
I'm not assuming the intended use is only to turn locos. In my case, the stub end of the wye is an 8 track hidden staging yard.
Yes, the number of relays, and the features, can be scaled back as needed.
Yes, the A frog can be hard wired to the south rail. As you can see, I omitted all frog wiring, only mentioning it was possible.
Note - I use Atlas Custom Line turnouts, which are feed thru. Users of PECO or other power routing turnouts will need gaps and wiring appropriate for those turnouts.
Again, based on my vast experiance with relays, I would avoid latching relays in favor of hold circuits.
I don't use toggles because of the need and desire to have control stations at multiple locations, local tower panel and CTC panel. And the lighted pushbuttons make a better user interface in a control panel.
The gaps between B and C assume two mainline blocks, which allows one train to exit/enter the wye, while another approches the wye. Again, no assumptions about the desired operations. And again yes, if this is just an engine terminal wye, it can be made much simpler - facts not in evidence from the OP or stevetx.
Since the B and C relays are there, the buffer circuit guards the turnouts in the two block senerio.
Maybe you are comfortable with the 1 amp Tortoise contacts, but I run four unit powered lashups pulling 50 cars, I'm not trusting them for anything beyond frogs or control signals. I know modelers who have burned them up......
And lastly, as a complete layout wiring practice, consistant methods and protocals make for neater, easier construction and easier trouble shooting if necessary.
Of couse as it turns out, the relay cab control system I installed for a fellow modeler, has been trouble free for a decade now.
as an engineer, i've struggled to understand others when they dive into a topic or answer a question without providing background or explaining the unque aspects of their problems.
BNSF UP and others modelerHe wants to know how to wire a wye in DC. ... He can't find anything helpful, and I cant really either.
i've made the assumption that the OP is not very experienced with model railroading or at least wiring.
i've found your circuits confusing until you explained how they fit into your layout. i think the needs of your layout and your preferences make it easier to understand your circuits.
i've felt misled when starting out in various hobbies, when i've tried to follow more advanced hobbyists who do things in ways that were correct for them but unnecessary for a novice to be concerned with, much less appreciate.
again, i've learned a lot from this discussion. another tool to consider for solving problems.
I am back with some explanation. I have been watching this thread, and (in my opinion) it is getting complicated. I work in dcc so that is why I dont know much about this. I also have a workable level of wiring knowledge (I can install a decoder), so that is not the problem. I appreciate the wiring diagrams, but frankly, they are over my head. Hopefully I didn't come across as non appreciative...
I'm beginning to realize that Windows 10 and sound decoders have a lot in common. There are so many things you have to change in order to get them to work the way you want.
If, as greg said, the A track is a stub foor turning locos - the same simple setup would work for DCC as well. There's never be a short, no need for an electronic autoreverser.
Yes, the Tortoise contacts are rated to carry 1 amp. But there's no way those little wiper fingers on a PCB trace are going to switch 1 amp. At least on a regular basis. They are fine for frogs because 1) noremally there is ZERO current flowing when the frog polarity is switched (unless you precisely stop a loco right on the frog befor lining the points - but you shouldn't get that close normally). And even if the loco IS parked with a wheel on the frog, other wheels will be on other parts of the turnout, so the current switched throough the frog should be minimal. At MOST, absolute worst case, a 4 wheel loco that picks up from only 1 wheel per side, parked on the frog, yoou'd have a max of one loco drawing current when the frog is switched - not many locos draw 1 amp these days, in HO and smaller anyway. However, oon a full reverse loop, or a wye that is turning an MU consist - now ALL of the track is powered by those Tortoise contacts, not just the frog. 3-4 units MUed, especially with sound decoders with keep alive (thus inrush) - you're going to be switching a lot more than 1 amp. Much better to use the Tortoise contact to trigger a relay with 5 amp or so contacts.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
BNSF UP and others modeler I am back with some explanation. I have been watching this thread, and (in my opinion) it is getting complicated. I work in dcc so that is why I dont know much about this. I also have a workable level of wiring knowledge (I can install a decoder), so that is not the problem. I appreciate the wiring diagrams, but frankly, they are over my head. Hopefully I didn't come across as non appreciative...
I assure you, no offense taken in any way. And I hope all my comments have been received in a friendly spirit as well.
I surely understand that many people do not have prior experiance with this kind of wiring. I 'm sure you could learn it, but I understand as well why it may not be important to you.
For me, and many others who have been in more advanced aspects of this hobby long before DCC, these concepts and methods are part of our experiance in the hobby.
I have used DCC, I understand DCC fully and have helped build many DCC layouts. It is actually this experiance with DCC that keeps me using DC.
Respectfully, the skills and knowledge base required for DCC, are dramaticly different then the skills and knowledge base for the circuits I published above. So again, I understand your position.
gregc sheldon as an engineer, i've struggled to understand others when they dive into a topic or answer a question without providing background or explaining the unque aspects of their problems. BNSF UP and others modeler He wants to know how to wire a wye in DC. ... He can't find anything helpful, and I cant really either. i've made the assumption that the OP is not very experienced with model railroading or at least wiring. i've found your circuits confusing until you explained how they fit into your layout. i think the needs of your layout and your preferences make it easier to understand your circuits. i've felt misled when starting out in various hobbies, when i've tried to follow more advanced hobbyists who do things in ways that were correct for them but unnecessary for a novice to be concerned with, much less appreciate. again, i've learned a lot from this discussion. another tool to consider for solving problems.
BNSF UP and others modeler He wants to know how to wire a wye in DC. ... He can't find anything helpful, and I cant really either.
I understand what you are saying, but I must say I don't agree, and I don't "operate" that way. I do not try to "guess" what peoples needs, experiance level, goals, and prior knowledge base are. I would rather they told me, but in the absence of that, I will still try to offer information. I try to avoid assumptions about others, but sometimes people take suff as condesending either way.......
I have been accused on here before of "talking down" to people because I sometimes over explain......
But I don't, and won't try to decide for others what their needs are. I just try to put well explained information out there for them to use as they see fit.
At every turn you seemed to assume you knew what the OP, or stevetx, wanted to do, and what they did not want to do, or what they needed to know, or not know.
Like some politicians who are sure they know better than I what is "good" for me....
Your mind reading skills may be better than mine.....
Back to the wiring.
DC is a completely different mindset of operation from DCC.
DCC assumes that everyone's highest desire is to be the engineer, to sit in the cab, to turn the lighs on, ring the bell and slide the throttle to the next notch.
Out of necessity, advanced DC looks at the "bigger picture" of how does the single train interact with the whole track "system" and how can easy and prototypical action be achieved.
That does require making choices in advance about operational goals in order to get the best result for those goals.
I once visited a large basement filling layout that had just one DC wireless throttle like the ones I use. The layout is a giant Industrial Switching Layout, the guy only runs one train at a time, he was not into sound, He has tracks he can kill to park locos. Pretty simple.
He does not need my advanced cab control or DCC......
I design all my layout wiring in advance, and build these circuits on the workbench. So hooking them up to the layout is no different than you hooking up some logic module to do the same stuff.
You will need the same inputs and outputs to achieve all the same goals. Logic modules require writing/entering code, my "code" is wires on a panel of relays.
I have described my whole control system multiple times on this forum, I suspect you have seen it.
It provides an operator experiance very similar to DCC with the following goals:
Signals, detection and CTC
Local tower control
Radio wireless throttles
Automatic Train Control - as in the prototype term, trains that run red signals stop automaticly - not an automation of the layout. This feature is largely "free", a result of not using common rail wiring, having totaly seperate power supplies for each throttle, and careful placement of gaps between electrical sections (blocks). Soon I may cover this feature in the thread about my layout move/reconstruction.
Simple easy to use control panels for turnout controls and CTC
It does all this for a good sized layout, designed for 8-10 operators, 30 staged trains, about 8 scale miles of mainline, and it does it for less than decoders for my 130 locos would cost.
I don't make assumptions about other peoples goals in this hobby, possibly because my goals are not typical.....