I have a layout I’d like to get wired up for DCC. I’ve read the basic advice on web page http://www.wiringfordcc.com/switches.htm and a few other places, but I still feel confused about how to apply this information in a switching layout like below:
In the interest of preserving sanity and avoiding too many misunderstandings, I have tried to labels various points of potensial interest in the layout by characters A through T, skipping I (India).
I will refer to the turnouts by the letter at the “heel” end of the turnout - ie at single track end of the turnout. The three topmost turnouts would then be turnouts A, B and E, respectively.
This is the entire layout for the time being - it may later become part of a larger layout - if so, the rest of the layout will be connected to the track sections labelled A and E, respectively - think of this as the “mainline”, if you will, with the rest of the layout being various sidings and industrial switching track.
DCC, all turnouts (including the three-way turnout and the double slip) are Peco code 75 electrofrog, the crossing is Peco code 75 insulfrog.
I plan to follow the advice to power route only frogs, not sidings. I need some advice on where to put 1) insulated rail joiners and 2) power feeds in such a way that this layout neither will short out nor make parts of the layout “dead” when I throw turnouts.
Is the simplest approach to just put insulation joiners on all the rails for the double slip and on both the frog rails and the stock rails on the frog end for the regular turnouts, and then put feeds at:
Btw - I just realized a neat little feature (which may have been obvious to everybody else but me for a long time already).
It is sometimes desirable to be able to refer to a layout diagram or something like that while reading a text or writing a reply. When you hit “quote” to reply in the forum, you loose the ability to zoom in on the picture in the original post.
But if you are using Internet Explorer it is possible to right click on an image in a forum post before you start to reply, and select “Open Link in New Window” - that gives you a second Internet Explorer showing just the image (full size).
Just thought that might come in handy for someone else, too.
I took some photo’s of the recomended method, my name in the thread is Gary H.
You will need to cut the jumpers from the inner end of the frogs and fit insulated joiners to both rails leaving the frog point itself. The above will show the principle.
Each set of points will have its own feed as shown by the wires (red and blue) in my example. This method will ensure that the whole of the point is live at all times and your not relying on the switch points to route the power (unreliable!)
That should get you started, anything else, give us a shout!
Thank you very much, Gary! I also found another helpful web page - this one in Norwegian, but the figures should be pretty obvious - the author of this other page has been pretty good about color coding his diagrams in a fairly clear way (right click on link and chose “open in new window” to read without losing this window).
Figure 9 on this Norwegian webpage was especially helpful to me in understanding how to feed power to the layout as a whole (as opposed to how to feed power to a single turnout).
Basically it seems like you feed every turnout, use insulation joiners on every frog rail, and then arrange extra feeds for “orphaned” rails (like the green rail at the bottom of figure 9).
As you have correctly surmised, your plan requres an electrical contact of some kind that thorws with the turnout to power the frog. Your proposed wiring scheme will provide good operation with an absolute minimum of short circuits and stalling.
Caboose Industries hand throws are available with the requisite electrical contact, as are Humpyard levers. Many folks make their own hand throws, incorporating a toggle or slide electrical switch in the mechanism to provide the contact. Usually a push/pull mechanism coupled to a wire in handle of the toggle or slide works quite well. The electrical switch’s detent can be also be used to latch the turnout in either position. I have even see home built contacts using strips of metal.
What will not work is using the built-in Peco over-center spring and simply moving the points with your finger. You somehow have to couple the point throw to that electrical contact somewhere. Most manual and non-Peco turnout motors work much better with the Peco turnouts if the over-center spring is removed.
Let me rephrase, to see if I got it right: the movement of the point rails must in some way be mechanically linked to an SPDT electrical switch in such a way that when the point rails move to the opposite position, the electrical switch at the same time change which of the two input terminals is connected to the output terminal on the electrical switch. The output terminal from the electrical switch then is then connected to frog part of the turnout.
That makes sense. I feel a little like hitting my forehead with some hard object for being so slow to understand this part.
Now I finally understand why the Peco turnout “motor” (which essensially seems to be a small electromagnet that will slam left or right a sliding center piece, with the sliding center piece holding a small rigid vertical metal rod that hooks into the throwbar of the turnout) needs the add-on PL13 electrical accessory switch or the PL15 electrical twin microswitch.
Here is an image of a PL13 (see image below, viewed from underside, where it is easier to see how it works):
Okay. Good to know, even though it means that my initial choice of Peco code 75 track - a decision made without too much thinking - apparently will end up causing a bit more work than a choice of Peco Code 83 would have made.
Code 75 means no insulfrog turnouts available - just electrofrog turnouts, and electrofrog turnouts more or less means that I cannot just move the throwbar by hand since I need the mechanical linkage to the SPDT to power the frog.
Mmmm - I don’t suppose I could just turn a Code 75 electrofrog into the equivlent of a Code 75 insulfrog with a few cuts ?
If you leave the Electrofrogs as they are from the factory, the points are linked to the frog with the jumpers you took a picture of. Moving the points serves as the SPDT contact as they change from contacting one stock rail to the other stock rail. Auxiliary contacts are not needed, and the frog is powered.
One downside to this factory arrangement is that the open point and its adjoining stock rail are of opposite polarity. The back of metal wheels can sometimes brush against this open point, causing intermittent short circuits. When it happens (not near always), it can be difficult to trace and resolve.
The other downside to the factory arrangment is the susceptibility of the point not to make proper electrical contact with the stock rail. A piece of ballast or similar can stop the contact from being made. That said, Peco does an excellent job of incorporating the latching spring and other measures to ensure good electrical contact between point and stock rail. Note that you can still use a separate contact to further guarantee power to the frog.
Your proposed mod of cutting the jumpers between the frog and points makes the points electrically independent from the frog. The frog now needs a separate power feed. The points will still receive power from the adjoining stock rail when the point is closed and/or can have a jumper added to tie them more positively to the stock rail. This mod eliminates the possibility of wheels spanning an open point and the stock rail, thereby causing a short circuit, and is encouraged for DCC operations.
