Kind of 'spitballing" here to figure out why my latest layout does not run anything I own. My weakest discipline in model railroading is wiring a layout. I was originally running DC and used the 'just wing it' method of wiring. Every so often I would wire the layout correctly and a actually got to run trains. Most of these layouts were small and simple track work. Generally the mainline was the main bus... and turnouts were managed by Atlas Selector and Controller circuits which were almost fool proof. Power Pack supplied 'the juice' to the mainline. Eventually I made a medium sized layout and created a 12 AWG bus circuit beneath the bench work. To this was connected a rather weak MRC 280O dual cab throttle pack. Since I did not do a second track for the other cab I hooked up to "Cab A" only. So I had a closed circuit beneath the bench work. I used Kato Unitrack on the bench work with parallel drops to the the closed circuit below. The Kato Unitrack was not itself a closed circuit... it was just a long run open ended and with a couple of #6 turnouts. Because there was a closed circuit below the bench work and power supply was hooked to that... did not matter that the Unitrack did not complete the circuit on top of the bench work. The one real issue with this scenario was that the MRC 2800 was too weak to maintain voltage as the locomotives moved further away from the connection to the bus circuit. I ran a few consists on this setup... as long as they were DC only. When I tried to do a DCC/sound equipped locomotive with an analog conversion box connected to the main bus. Results were disappointing because the output voltage was too weak to maintain power to the decoder. So now to a slightly smaller layout similarly wired as noted above. This one needs to be DCC because I have committed to convert most DCC ready locomotives. Since I have a continuous run without a provision for different power districts... whatever is causing the lack of power will need to be totally removed. I will be using terminal strips with spade connectors every few feet to create a circuit that can be diagnosed if wiring fails in a section. Every 10 to 15 feet can become a power district with a booster to keep voltage more constant and prevent loss of control of a consist. So... how does this proposed electrical rework seem to you far more knowledgeable electrical experts. Suggestion are very much welcomed.
This sounds like it was adequately wired, but apparently it was not. What do you a consider a "medium" sized layout? What gauge and how long were you feeders? It doesn't matter if a power supply can provide 1 amp or 10 amps, voltage drop is entirely dependent on the current draw of the train and the resistance of the wiring. If the train slows down when far from the power pack, having a more powerful power pack is not going to help (unless that power pack can output more voltage, because you can increase the voltage to overcome the voltage drop, but then you'd have to turn it back down as the train comes closer to keep it from speeding out of control). Definitely should not need a booster every 10 to 15 feet unless you plan to run multiple large consists. My current layout is about 20 feet long running off a single 2.5 amp Digitrax Zephyr. I can run several locos at the same time with no power issues, and it's actually not wired nearly as well as your above description (it's just a temporary test layout).
I forgot to ask, judging from the thread title, I'm not what exactly your current situation is. Are you saying you currently don't have any power. if that's the case, it's most likely crossed feeders or a reversing section somewhere causing a short.
I'm also a bit puzzled by what you describe. My current layout has a 160 foot mainline.....it's currently in the testing phase so I just have an old Bachmann power pack hooked up and voltage drop at the farthest point is minimal. I'm in an Ntrak club and our layouts can reach 100+ feet of mainline. On that layout there is a bus around the layout. and a feed every 4 feet. We have no problem maintaining proper voltage around the layout despite the farthest point from power is 50 to 60' away. When running DCC, we connect by breaking the bus loop and hooking to one side.......this means the buss is 100 to 120 feet long, although power can still move thru the track as well (buss open, track closed). The DCC supply I use at the club is only 2.5 amps and I usually have 3-4 locos running and again no problems with locos slowing down. Have you tried any other power supply? Or just switched over to the B cab? I sounds to me like the power supply may have gone bad. Without seeing a diagram of your actual wiring it's difficult to diagnose a problem, but I can't think of any scenarios where the trains would behave the way you describe. I had a similar thing happen to me, but I made the mistake of wiring multiple cabs and using common ground. Running one train, everything worked perfectly, but if you tried to run 2 trains, because everything was hooked together thru the common ground, the blocks would add or subtract........so if one train was trying to run one direction at 6 volts, and another train was trying to run the opposite direction at 4 volts, the voltages seemed to add up.......so 6 + -4 = 2 and both trains would run at the equivalent of 2 volts. If both trains were set to the same direction, they would run at 6+4 or the equivalent of 10 volts. I had to go back and double insulate every block to get things to work properly. You say you can't run ANYTHING you own.........unless you have some really old,crappy locos, they should run on 3 to 4 volts (not sure if I understood what you did with the DCC loco, but DCC/sound locos generally need A LOT of DC voltage to get moving) so again, it leads me to believe the problem is your power pack.
The "medium" size layout had about 72 feet of buss wiring running beneath the layout as a closed loop. There was only about 30 feet of Unitrack placed on top of the bench work. That track was in a line that did not close the loop. There feeders from the track to the buss every couple of feet. The power supply connected to the buss was an MRC 2800 dual throttle which only puts 14V per cab if I understand the numbering system MRC uses. It is not a powerful unit so the more powered locomotives on the track the slower they would perform unless more power is supplied from the throttle. The new layout has about 50 feet of buss wire salvaged from the prior layout. This wiring is rather old (10+ years) so my concern is that this wire may have internal breaks which is leaving an open circuit that won't supply power to drops. I have only a few feet of new Unitrack on top of layout. None of my locomotives (old or new) will budge. So I am going to replace all the old wire with new wiring. I just wanted to make sure that I don't take out wiring only to find out a problem will persist. It is difficult for me to get under the layout... lots of stuff to move. I prefer to do this rewire in segments which can isolate issues in the future.
If you don't have a lot of track, and you have feeders in, try breaking the track into blocks, and then start adding more blocks and more feeders.....keep adding till either you find a problem, or you finish your loop. Age shouldn't affect the wire.....only the plastic insulation. If it was an insulation issue, you would be getting a short. Also 12 gauge wire isn't overly prone to "breaking" from flexing.
Thanks for the advice. I will be using some terminal strips to set up segments beneath the layout which can isolate any short. No sense in fidgeting with the old wire. I will be using new 14AWG wire with #8 spade connectors. Meanwhile, I will set up a new Unitrack set with a Kato power supply and test all the locomotives which didn't run on the layout. My guess is they will all run fine, proving the wiring is the culprit.
Do you have a meter of any kind that you can use to test voltage? You said nothing runs, but do you get lights or anything else on the locos? Most better (yes your MRC qualifies as better) powerpacks have a breaker in them of some sort. Usually it resets automatically. Is it possible you had a short at some point and it failed to reset? If you had a meter you could check for output from the powerpack. Another "test" for your locos is to use a 9v battery (the ones with the 2 posts on top). Simply touch the battery across the trucks (one post to each side) while holding the loco in your hand.......if the loco is working, the wheels will spin. It would let you know if your locos are all working.
If you don't mind me asking what is the physical size of the layout. 4' x 8', 3' x 5', 2' x 4' ( I have two of these for mine ). And are you just trying to do a simple oval loop for now for testing?
THAT's the way to do it. Rewire it if you have gremlins that cannot be traced. Since you are smartly going to the trouble and expense of rewiring your railroad, do the following: 1. Choose a STRICT wiring convention of color. Identify a NORTH rail and SOUTH rail. Keep the color consistent to each rail. 2. Get a good label maker. Identify every wire with a printed label every 4 to 6'. Identify the wire as to rail, block, and/or power district. ALSO.. label each of your terminal strips as to block and power district. Label each terminal group as to North rail or South Rail. Future tracing becomes a snap. 3. Buy a good pack of Sharpies and identify blocks and nodes below the layout as your pulling and fastening wire to temp label before you apply the printed labels.. Another effort that makes tracing a snap. 4. Record all of the above in a note book. 5. Apply power and check each block and district node as you complete the wiring. Most of all, research and read everything you can on DCC wiring and organization of wiring. Wire management does two (2) things. A. It allows you to set a rigid convention. B. It allows you to better trace where problems occur. The theme to all above is setting yourself up to be able to trace everything for ANY issue that arises. 9 times out of 10, the more you follow a convention, those gremlins will soon start to go away. Good luck!! When taking your time and making sure you are organized, wiring becomes both easy to understand and trace.
This is in a small bedroom about 10x10 plus closet area 2x6. The closet portion is supposed to house a helix which is not started and no wiring yet. The bench work is along the walls 16" to 24" into the room. At the entrance to the room there is a 3' area to allow door to open. The area at the door opening is 4' into the room and is supposed to have another helix to make a duck under from the closet helix. This also not wired either. I am considering ditching both helices to keep things simple.
MRLDave, You brought up several good points I'm going to have to try the 9v battery directly on each of the locomotives. The meter does not register any current on the test rails connected to the buss. Never thought about a short in the pack... but it does light up when plugged in. Thanks.
Our club had a number (6?) of MRC powerpacks, and one by one they all died. As you noted, they aren't super powerful and we tended to push them to the limit........we repeatedly heated them up by running too many locos (usually 4) and they would do a heat induced shutdown......eventually they would stay in shutdown and never work again. That was a thermal shutdown, and what you have appears to be an electrical shutdown, but the same logic applies. I believe the pack will light up to tell you it's getting power........doesn't mean there's anything coming out the other side.
And the story gets weirder. So I decided the easy route was to use the 9v battery. I had an allegedly "new" Walgeens brand battery, still in its cellophane wrap, handy which I opened and put on the trucks of about 7 different locomotives. No life from any of them. Now I'm worried that there is some cosmic anomaly that doesn't allow DC electricity to flow in the room. So I then turned my attention back to the two MRC power packs. I put the alligator leads on the AC accessory terminals to see if there was any juice there... I got sparks galore when rubbing the clips... so AC terminal works. Went back to both Cab A and Cab B... tried the same thing rubbing the clips together... no sparks no life from either. Tried the clips on the locomotives... nothing. Scratching head in disbelief... AC works... DC doesn't work. Cosmic anomaly seems real. Then... it dawned on me that batteries have limited shelf life even if not used... and I happen to have a simple battery tester and other 9v batteries which are less than 1 year old. The "old" Walgreens battery only registered 5.4v on the tester. A new Eveready Alkaline 9v measured at 9.4v. I took out a 30 year old Atlas/Kato SD9... and sure enough it started up as if new. Repeated this with old Kato F7A and it was running like a Kato should. Same happened with an Intermountain F7B, Walthers GP9; and, even a first run Model Power 2-6-0 Mogul ran great... WOW! All locomotives did not run though. A new Arnold U25C failed as did a first run Atlas SD50. These locomotives will need to be serviced. So the two MRC power supplies must have issues... they are old units from the 1990's and were used on a club layout for a while. Perhaps they did overheat and short out the DC. Apparently no issue using them to power AC accessories. Still going to rewire the buss to a more manageable method though. Thank-you for your help and suggestions!
