*screams* I have been building model RR's a for a few years now, and this one's giving me fits!!! Number one, the helix has dramatic voltage drop since the mainline was finished. The engines act like there's a huge voltage drop, yet the rest of the visible mainline acts normally. The rails get warm, for some reason, and only in the helix area! I dropped feeders, and when I connected them, the DCC command system (installed today) shorts, even when I check the polarity, and follow the rails around to ensure I have not mixed anything up, it still shorts. I disconnect the helix feeders, and attach them, temporarily, to the bus, one-by-one. It shorts out when I attach a certain few feeders. Not all the same polarity, however. I connected a couple incorrect polarity feeders to the bus, and it didn't short! What's going on? The DCC command box goes into overheat shutdown as well. It gets very warm. Argh!!!!!!!!!!:angry: :angry: The helix rails getting warm is NOT normal, I dunno what's going on. Can anyone make sense of this nonsense?
Hemi: Your helix has at least one reverse loop and possibly two, judging by the photo's of your layout in the Layout Design Forum. I can't see the complete top to bottom view of the track work entering and leaving the helix. You have one reverse loop where the track forms a wye at the top. I can't make out the bottom tracks, but you probably have the same thing there. Stay cool and run steam.....
Hemi: If you have the same track arrangement as discussed a couple months ago, you should have 2 reversing sections that are insulated with plastic joiners on both rails at both ends: The first is in staging. The track that returns from under South Draw should be the reversing section...not the staging tracks. Insulators should go in both rails at the turnout just before the staging reversing loop ties back into the track to the helix and at the other end of that reversing loop track near South Draw. (FWIW, if you put it where the track reappears after looping under South Draw, you will have enough length to reposition a train from one staging track to another without having to enter the reversing section...although with DCC reversing loop protections as sophisticated as they are, there really isn't any problem with tripping the reversing circuitry.) The second is in the arm of the Y at Plain that goes down to Staging. Insulators should go in both rails where the arm connects into the helix and also in both rails where that arm ties into the turnout in Plain that makes the Y. Electrically, you have a loop from Plain up the hill to Crescent and back down the helix to Plain. The lower part of the helix from Plain to staging is like a siding off of the main (upper levels) loop. If you've wired Plain up to Crescent with right side red, then the track at Crescent should have the red wire on the back rail, the inside rail of the helix should be red, the front rails through Plain should be red, and the front rails in the staging tracks should be red. The feeders for each of the reversing sections should tie into a separate bus (one that is coming from the reversing loop protection circuitry). Clear as mud??:teeth:
You only have to wire one set of feeders in the reverse loop to a reverse loop module/switch. If you use more than one set of feeders, you can't wire them to the main bus lines or they'll short out. The second set of feeders to your reverse loop module/switch should be the track immediately adjacent to the reverse loop. You're shorting out because your feeders inside the reverse loop are wired to the main bus lines. See my Blog about reverse loops using DCC. It's really easy wiring using DCC. Two wires in the reverse loop go to the reverse loop module/switch.The other two wires to the reverse loop module/switch go to track outside the reverse loop. The reverse loop must be isolated at both ends with plastic insulated rail joiners. Stay cool and run steam.....
The reversing sections are insulated with Atlas insulating joiners, both of them. I don't see how the helix would be another reverse loop. I think that if polarity was wrong, the layout would short, and not operate. The visible mainline operates normally. The turnouts I used are reused from my last layout, aslo DCC. These are exclusively Peco Insulfrogs. The issue I don't understand is the current drop on the helix, and the resistance (or whatever it is) that is heating the rails, and whatever is causing overheat shutdown on my Digitrax booster.
The clue is the fact that the rails are heating. There is absolutly no way the rails can heat if the wireing is correct. Timbuck Who?
Your problem lies in the track in the first elevation which forms a wye entering and leaving your reverse loop. I can't see what you have on the upper level of the helix Stay cool and run steam.....
I haven't wired any feeders to the reversing sections, for that reason... Here's a quick trackplan.. Pardon the helix drawing, (I don't have the patience to draw a true spiral helix in MS Paint) there are only 2 turnouts in it, on the second loop; and they lead to the insulated, reverse loop/wye at Plain. I understand the basics of the reverse loop, and installing feeders, but the rails heating up, and the booster overheating and shutting down baffles me.
I can't add much to this as I already don't understand most of it. I am sure PSG is correct about the problem. Wouldn't the first step be to identify the reverse loop? If you can't find it, you can't isolate it, or whatever you do to it. I haven't seen a track plan here that I think has a reverse loop, but I may be wrong. (I looked for one in Hemi's RI album.) Reverse loops can be hard to detect if you are inexperienced, and sometimes I can't see them. The more you look, the easier they are to identify. Just my two cents. [edit] Oops! The image posted above is more detailed than I had seen before. I will have to check that one.
I understand the wye, and I have one leg insulated and isolated, no feeders... Here' what the top of the helix exits to:
If you haven't wired the reverse loops in the helix, why is the track within the loops overheating and causing the system to shut down?? There should be no current in the helix. Stay cool and run steam......
Flash, I have, and isolated 2 reverse loops--Staging return, and the wye at Plain. I don't see how there's any more, the rest are sidings, or treated like sidings, electrically.
Hemi, Could you have a pair of pliers or a steel pin crossing the tracks? Go look again. That's what happened to me four years ago.
I would remove all wiring from within the helix to where ever you've wired it to. Once that is done, you should have no short circuits. Your helix is "live" now and causing the problem. Isolate the helix from any wiring at both ends. Stay cool and run steam.....
The leg of the wye in the helix is wired, and also gets current from feeders near the Tunnel 23 area, at the top of the helix. The leg fo the reverse wye in the helix that is isolated is the ouside leg, in the pic you posted, the farthest leg. The foreground leg is wired normally. I installed feeders in the helix, but connecting them somehow shorts the layout. Maybe pics would help? The (from inside the helix) inside rail in the helix is wired with a white feeder. The outside rails get black. Following the polarity to the top, the track s-curves to Crescent. No wye here. The polarity doesn't change, but the inside rail becomes the outside, and are treated as such. Is this wrong?
There is a pair of pliers lying across the staging yard tracks in the last picture. Wouldn't that cause a dead short?
The Digitrax booster would detect the short, and shut down... The helix does operate, somewhat. I have some massive resistance that heats the rails, and causes speed drop. I like PSG's suggestion of isolating hte helix, and disconnecting all the helix feeders.
Old picture, used only for illustration...:zip: If you stretched out the helix, and the mainline, it would just be a long oval, right?
