A poll for us dinosaur DC users, do YOU, or your club, use common rail, now or in the past? And if so, do you have problems with it that are solely because of the common rail, assuming it is wired correctly as per NMRA and several Kalmbach books (and NOT Atlas!, with the common rail connected to at least a 16 ga. bus wire, and each throttle has its own power supply)? This is not intended to stir the pot about common rail vs. DPDT switches nor to start a discussion or arguments; just to see how many of you use common rail and if it works for you, that's all. I'll go first. I use common rail, have at least 20 blocks, SPST's, and have no problems with it attributable to common rail . John
You have me wondering whether I was using common rail or not. Several years ago I dismantled a layout I ran for 25 years, but have not gotten my new layout far enough along to run. I may not remember exactly what I did. I believe I remember that I gapped only one rail between blocks (didn't have any reversing sections) and I used DPDT toggles for my blocks, except dead-end spurs. I called them "satellite blocks", fed from the through block to which they connected, but the satellites could be turned off. Never had any problems attributable to common rail. However I may not challenged the system fully. I'm not sure I was EVER running 2 trains at once. Wanted to have another operator join me for a session but never did.
I gap both rails but gang the commons together, so I only send 1 wire to the atlas selectors or control toggles. Except for the track feeders the wires are all 16 gauge and I believe I have 37 electrical blocks.
I do not use common rail. My dad and I are both electrical engineers and when I was young he basically forbade it. Which is not to say it won't work, only that the man who knew electricity forbade it.
We are talking about Cab A and Cab B type operations? I tried the common as per the Atlas sliders and it didn't work for me. I lost two transformers and 4 maybe 5 locomotives. To my rescue and under the tutelage of one Mr. Hunter, I added two more wires to the system, purchased DPDT toggles and set-up my blocks accordingly. I still consider it the safest way to wire a layout. No common rail/wire for me.
club layout was formerly common rail. Some brass engines with can motors really don't like anything but Pure DC. we had some narrow gauge modelers who got some K-27's? (I think thats what they were, this was a few years back) and they buzzed like mad on common rail. When we converted to bi-wire they became pretty quiet engines, and the final conversion to bridgewerks throttles on the narrow gauge lines resulted in them becoming completely silent. We had a series of issues with the common rail outside of this that resulted in it being pulled.
John and I can't win any bets this way. We have a dinner hanging in the balance here. No fun going Dutch treat. Jump in with your two cents and know that neither one of us will put your down for your take on the subject.
how does one common rail? pardon my ignorance but I've only been legitimately model railroading... let alone N scale for about a year.
Tipping the scale. SP&S, that's possible. You can have one track as your main and not have any blocks and you'd be operating a common rail. So to speak. John A., looks like lunch is on me. LOL
Common rail refers to having one leg of the power packs all tied to a common bus rather than having each block fully isolated and connected to one pack at a time. I don't understand why it's supposed to be better. KISS and basic DC wiring tell us to avoid it like the plague, but there must be some reason people do it.
Had a similar experience to another poster here. My Dad was also an electrical engineer and my first HO layout back in 1960-something was not wired common-wire. Each block was electrically separate. Since then, all my N-scale wiring has also been non-common-rail, which I believe is just asking for trouble. In the four years since I've totally ripped out all my rat's nest of DC wiring and eliminated all those toggle switches and relays with Digitrax Super Empire Builder Radio DCC, I have been extremely pleased with non-common-rail wiring, feeders on every piece of rail, sub-buses, Anderson Power Poles, Genuine 3M IDC's and low-ox, high-purity, many-wires, black & red speaker zip wire in 12 ga....like happy as a clam.
No common rail for me. Actually, I'm not sure what it is but when I started the guys were all against it. Why would the engines "buzz" on common rail but not on other types? Thanks.
Initially started to wire common rail and switched before I even finished. Our club does not use common rail either.
Flash, the only reason an engine would "buzz" on DC common rail if it was wired incorrectly. It has to be done just right, as would ANY type of wiring on a layout. On my layout I have 29 blocks, two cabs, common rail, and another model railroader from here and I have tested it thoroughly because he does not believe in common rail, either. He told me that my layout is the first one he's seen with common rail and no problems, and to quote him, trains "ran like a swiss watch". So I guess I must've wired mine correctly. Yes, I have can motors as well.
To understand what we are talking about here see the illustration posted above. So what's the fuss all about? John and I want for you to wire your layout safely. We would like to see you avoid the pitfalls that other's have made. That's what all the fuss is about. That be it in a nut shell. In response and support of what John A. indicated in his last post. Guilty, I said those things. John, is quoting me and it's ok to quote me. I did say, his layout runs like a "Swiss Watch." He's also right in that I would never wire my layout to a common. No Sir. I do not feel and would want others to hear me when I say, it's not the safest way to wire your railroad. You can quote me on that. Now back to John's "Flash", he has wired his layout correctly as per instructions using an 18 gauge bus for the common. Yes, I've checked his wiring. Looked at the SPST toggles he's installed. Operated his trains, tested for symptomatic behavior (I will describe later), followed-up with a voltage meter and I can't find anything wrong. He has done something right. He still, won't tell me his secret. Actually, I don't think either one of us really knows what the secret is and yes, it is a first for me. Am I starting to repeat myself? OF'ers syndrome. My analogy. Keeping in mind I'm not the electrical engineer here. YOHO and other's would most likely do a better job of explaining the following: I suspect, one of the power packs he uses is modified to handle common rail/wire. An AristoCraft made for HO and Garden railways. I believe it has filters that filter out the conflicting currents. Then I learn, yesterday, he has used another transformer and had the same results. Huunh? On top of that he is using a Control Master 20. I saw two returned to a LHS, I worked for. Owners said they wired them to a common and blew out the Momentum and Brake features and the throttle was stuck on Run 8. Other MRC types returned in the same condition, same complaint. Not good news. In the words of an electrical engineer I talked to who was in charge of Pomona's HO Club Layout (Sorry, name of club escapes me right now and so does his name). Before I get to that, I noted that when someone tried to run a train in the opposite direction of the others, the train locomotives would stutter, acting in a halting fashion and even stall. All to familiar! I made a comment to one of the members saying, that's your common talking. The electrical engineer over hearing me was kind enough to step out and talk to me about it. Explaining: What we were seeing on the layout was the current from one transformer looking for it's own ground. In other words as it looks for the ground it can cross over a locomotives electric motor causing the unwanted activity. Take a locomotive going eastbound with it's power set to that polarity. Now try to run a locomotive westbound with the polarity in the opposite format. Running both locomotives at the same time. Now the trouble starts. This current looking for it's own hole/ground will cross over the electric motor, impeding it's forward motion, causing said symptomatic behavioral problems. You could safely say, both positives working against each other. I will add here: If the locomotive is sitting it can hum and possibly creep along the siding or spur it's sitting on. You'd need a quiet room to hear this. How? Good question. A SPST toggle set to center off will not shut off both rails, just one. The other side or rail has current feeding to it and is still hot. You haven't shut off the power to the track completely. Said locomotive will hum and if you listen closely you can tell it doesn't know the tune. Point is: You can only shut off both sides of the rails with a DPDT toggle. An SPST although perfect for the those who wish to wire in a Common, does not shut off the power to a block, leaving half the current on. Can you see potential for a short, locomotive heating up, possibly a melt down or burned up motor? Oh, I almost forgot. On my common wired layout. I saw and heard my locomotives do all sorts of strange things, as here to fore described. Lost two transformers and six locomotives. Yes sir, and I would not want to see that happen to you. You won't mind if I get back to my layout and get some LED's and CCTV's installed. No common on board and there never will be. I've not been as lucky as John A. That be true! Still in awe of his layout but keep in mind he is an Architectural Engineer. Kind of like the student talking to the teacher...if you know what I mean. That wouldn't be a first for me...student versus teacher. Actually he is easy to talk to but has selective hearing. I didn't say that, did I? COL John...Salute. You made it work.Like a Swiss Watch.
Common rail can make can motors and other more modern electronic equipped engines buzz. Even if the common rail is wired correctly. Our layout was wired up by an ex-army engineer who was deadfast common rail until he saw the improvements afterwards. If all you ever run on common rail is older motors, such as pittmans, and athearn/atlas stuff, than yes a buzzing motor would indicate that the layout was wired improperly. However can motors are extremely sensitive to how filtered the DC is. We have a lot of brass hats at the club here, and they run a lot of brass steam that have can motors. Ever heard the resonance of a vibrating can motor encased inside a brass shell? wow, that get irritating fast! These motors were so sensitive to DC that the switch to bi-wire fully isolated blocks only made them quieter, and did not stop the growl. We noticed that on the MRC Tech II's we had they would buzz, but not too much, on the Tech IV's that had pulse width, they would buzz louder. One member took an engine to a large hobby shop up north that had bridgewerks throttles. Bridgewerks makes filtered DC throttles, this filtered DC turned out to be just the medicine the doctor ordered for these engines. Now they run pretty darn silent! on a side note to go along with what barstow said about the two positives above, place a sound equipped engine on common rail, particularly the blueline stuff that BLi made. Listen to the bell and horn go nuts when you run more than one train at a time. The circuits on board think the polarity has been reversed and are doing what they're supposed to do.
