Ntrak wiring standard change

In case any Ntrakkers have not visited the Ntrak website there has been a change in the wiring standard. The RP that was initiated about six years ago is now the new standard. So today 12 gauge bus wire and Powerpole connectors are required for any new modules. Older modules can still be used but the CJ plugs either have to be replaced by Powerpole connectors or the module owner has to supply conversion cables to convert the CJ plugs to Powerpoles. This is the immediate impact on most people. Previously under the RP it was the module with the RP wiring that had to supply the conversion cables. Naturally this applies accross the board as it is now the Ntrak standard. However, as in the past whatever individual clubs do on their own is up to them. So as long as your club sets up layouts by yourself you can continue as you did in the past but if you combine with another club then the new standard will apply.

I don't know if this was publicized in the Ntrak Newsletter as I haven't gotten one in a long time for some unknown reason. Our club usually covered that out of our dues. So I don't know if not getting a newsletter was a local problem or at Ntrak. Anyway the issue generated some discussion on the Ntrak yahoo groups in which I initiated and participated until the moderator shut it down threatening everyone with expulsion from the group. In any event, like it or not, what was previously a recommended practice is now the law. When the discussion on Yahoo Ntrak groups was shut down we were getting to what appears to be a movement to cleave Ntrak into two groups called "Ntrak Classic" and "Ntrak 2.0". Does anyone have any information on this plan?

 

Power Poles are a very good idea, but alas I am leaving Ntrak because 12 gauge is overkill. For DCC operation, which is all I do, 12 gauge has 20% less conductance and 40% more inductive reactance than 16 gauge wire. This can be mathematically proven if one understands advanced calculus and electromagnetic field theory. 12 gauge was an empirical measurement not a scientific analysis, and it was done more for DC operation than DCC. DC conductance and resistance characteristics are totally different than the DCC waveform and results will not be consistent. It will not necessarily work for everyone.

If NTrak wanted to do a more complete specification, they would have looked more at the DCC side of the house and also did a qualitative study on the quality of the wire used. The NTS Ntrak DCC layout had real problems because of the low cost, low quality wire used in a power district that was wired per the New Standards. So much power was lost in the wiring that only a couple of locomotives could run at any one time in the power district. So the 12 gauge wire is not the solution all by itself.

There actually should be a separate specification for 100% DCC layouts that are not held the same for DC operation.

This new adaption of standards is like all else with the NMRA and NTrak, one step forward and one step sideways. At least it is not a step backwards.

 

Our club has been steadily switching to power poles on everything and problems have been decreasing as we do it. Anything to get rid of those horrible 50's era cinch jones connectors is good in my eye. We have not seen any issue with 12 gauge wire and since many of the modules have been converted, we no longer need to run a second feeder set to our loop. For a while, our system tapped in at two places in the layout to cover voltage drop on the back side, away from the main power modules.

I would rather see overkill than what some of our older modules have, zip cord. I come from a car and home audio background and the wire specified is fine for high frequency use. It's basically high end 12 gauge speaker wire that we would install in $10k high wattage car stereo system. What is the big deal anyhow? The average person builds one or two modules, it might cost them $10-15 and an hour of their time to convert a module to the new standard, not a huge amount in the grand scheme of things.

 

This did run in the NTrak newsletter, which I occasionally receive. I don't remember what issue.

This isn't a whole lot different than in the past, given that nobody is REQUIRED to convert existing modules over. The jumpers used to be required from Powerpole users at a meet and now they are required the other way. In practice, I am guessing most meet organizers will have some of these or know someone who does, so I don't think it's going to be that big of a deal.

After spending the better part of our weekly meetings for a couple years converting wiring done ALMOST to the original standard over to a much more robust PowerPole and 12-ga wire standard in part to facilitate our DCC conversion I am quite glad we did it, and I learned some very important lessons about not cutting corners along the way.

I don't really think 12-ga is overkill for larger meetups where DCC is being used. Not only does the power need to get through but the signal strength needs to stay strong. You don't want to run right at the capacity your wiring can handle or you'll start having problems.

Adam

 

WOW!!!! Where were you when I needed you. The committee who devised the new standard was composed of all DCC enthusiasts and the new RP now standard was to address the voltage drop issue that plagued the large DCC mega layouts. They acknowledged that the new wiring standard did not solve the voltage drop problem but only reduced it so that they can get by with fewer power boosters. I opposed it because in my opinion it was indeed overkill and it made all of Ntrak pay for benefits for the DCC users and that benefit would only be for large layouts. The average Ntrakker at his home layout would probably not benefit. In analog DC there also is a voltage drop over distance. But it was alleviated by additional power feeders to the bus just the same as we all provide more than one power feeder to our track.

 

How much consideration was given to the new fire codes that have eliminated (in some but possibly not all venues) the power strip ganging?
Could that have been a contributing factor in requiring heavier wiring for the track power feeds?

 

Actually, the RP was published before the blow up on daisy chaining extension cords and power strips. The same committee was asked to work on an acceptable method for supplying 120VAC that complies with code because we were already available.
Daisy chaining extension cords and/or power strips has always been unacceptable practice. A power strip is considered to be an extension of the house outlet. One is permitted. An extension cord is considered an extension of the appliance. One is permitted. So you can have a power strip plugged into a wall outlet with half a dozen extension cords connected from it to half a dozen appliances. Use one extension cord from the house outlet with a power strip on the end and it is a code violation. Frankly, our load on the daisy chained power strips would normally not be a problem. Most inspectors would probably give a pass if they were given the proper figures by a knowledgeable NTRAK'er. Problem is you can't always count on those individuals to be present when the inspector comes by. Sometimes the inspector is just having a bad day.

A few dormitory fires with tragic deaths brought the practice under closer scrutiny by the authorities. Two NTRAK shows were shut down by inspectors. That got the committee working on alternatives. To this day, my club has never been cited for daisy chaining. BUT, I work for the Balto Housing Authority's construction division which is just a couple of floors up from code enforcement and across the street from the Fire Marshall's office. Every inspector I've asked including their director tell me the practice is a code violation.

Martin Myers

 

Well depending on what year this was done I was either teaching Graduate level courses in Electromagnetics at Stanford University or I was building up my company. In either case, I was not yet a social model railroader. I did my own thing with trains and PC computer controlled DC power supplies. I did not really know about Ntrak until 2005. And when I saw the specification for a control system with no feedback, DCC, which is part of the basic definition of a control system. I tried to get the NMRA to take another look at things but was soundly rebuffed. So I have not really cared what they did from that point on. It was obvious they were intent on a seat of the pants approach instead of a proper analytical approach. If they did their convolution integrals and Fourier transforms to see why the limit is about 300 feet before the DCC signal degrades due to dispersion. There is a process called the Harmonic Extinction function in periodic waveforms if there is too much reactive power stored in the higher order harmonics. In the case of DCC, the 23rd and 52nd harmonics have sufficient reactive power to feedback to the fundamental frequency out of phase. This causes the original signal to be extinct due to the reactive power reverting to out of phase real power after a distance of just a little more than the 300 foot limit. The dispersion effects of the wire medium shorten it back to about the 300 foot mark. The mathematical analysis is about 65 pages of calculations.

Things like twisting bus wires are anecdotal solutions which means under specific circumstances, it may help, but it is not a consistent solution. I tested the twisted wire approach on my programming and break-in layout and found that it caused more problems rather than helped anything. I was getting spots on the rails where the locomotives would stall. Track was clean, as soon as I untwisted the wires, the dead spots went away. The idea of RC terminators is similar. But unless you know what frequency to use and what type of filter to use; this is also anecdotal. The frequency to filter is not the Pulse repetition frequncy of the carrier, it is not the carrier frequency, it is at the frequency range that represents 60% of the total signal power due to the Square wave nature, the frequency content is much different than most people realize. And it should be a bandpass topology, not the RC lowpass topology that is being promoted.

Using real science to solve the problems would yield much more consistent and repeatable solution than anecdotal experiences celebrated as solutions.

 

Okay that last post was way over my head so let's bring it down to my level. How does this all relate to the voltage drop issue and the size of wire used? Are you saying it would be better to use a smaller wire than the 12 gauge as specified?

 

Sorry about that, I was tired and the engineering filter was disengaged.

What I am saying is the the move to 12 gauge wire is fine for DC operation. But there also is a case for smaller gauge wire with better quality material. The move to 12 gauge was made by looking at the American Wire Gauge chart. The problem with that is that those results are only valid for DC and 60Hz normal sinusoidal AC. It is not valid for higher frequncy operation like the 10 KHz DCC frequency or is it valid for the Square Wave. There is no reactance in a DC signal, there is just power and and material resistivity losses. Another problem is the standard wire that was used, it was what was then (1946?) commercial grade wire which is considered today as pig copper. It was not very pure and no attention was paid for higher conductivity wire because it was for plugs and lights. Today, there are much better materials and much better copper alloys to use for wire that has a higher quality material with less resistive losses than the wire tested back then.

This is not true for the square wave pulse signal that DCC is using (using the American Wire Gauge model). The square wave is made up of an infinite number of sine waves and infinite frequencies. In these other frequencies, some of the power is transferred into the harmonics of the base signal. The energy that is stored there is the reactance. If this energy returns to the base signal out of phase it causes harmonic dispersion. This is the key point for the next statement.

Smaller gauge wire has less reactance than larger gauge wire, which means that the dispersion from the harmonics is less, so the quality of the signal is higher.

I have tested this using a 50 set of modules and end fed all of the buses. I used a very good quality of 16 gauge wire and all powerpole connections. 12VDC was applied to one end of the module set, and the voltage at the other end of the set was 11.25 VDC.

I re-ran the test with DCC and at the starting end, the voltage was 12VDCC, at the other end it was 11.55VDCC. DCC lost less power than DC.

DCC lost less voltage than DC did.

 

I honestly haven't read the standard, I just know what our club is using, which is very high grade home theater 12 gauge speaker wire which I am very comfortable with. I would use it in audiofile quality sound system installs so it is good enough for model trains. I can see a problem using any old 12 gauge wire but as I said, things are getting better for us as we upgrade things.

One other thing you are fogetting, the signal is also piggybacked down the rail, not just the buss so there is some effect there also. You are not relying exclusively on the buss to carry signal, although it is doing most of the work.

 

Until every model railroader in the world is using DCC modular systems such as Ntrak and T-TRAK have to have some compromises to accommodate DCC and DC rather than being optimised for either. It's ok if your modules are only ever going to be used on their own but once you want to put them in a layout with other modules, or you want to invite other module owners to take part in your layout, you have to follow the manual.

I think it's good that Ntrak is at least starting to get out of the 1970's and acknowledging changes that have come to N scale since the days when running longer trains than HO was the only way to show off our scale. What will be next, trackwork good enough that you don't need pizza cutter flanges?:tb-wink:

 

Chester,
David (DCESharkman) is also a DCC proponent. I don't think his inclusion would have met your needs. He and I have had some exchange regarding the RP. Unfortunately, I do not think you would be happy with his recommendations as at least one requirement would be to use a better grade wire. Think more $$$$. That would still cost more than the old zip cord most of us were picking up at the local hardware store. This would be to carry the DCC signal better.

I can tell you there was at least one DC only member of the committee who stuck it out to the bitter end. While I'll not divulge his name to you here; I'm pretty sure you know him and I'll be happy to fill you in at Bedford in a few weeks. I'm usually right across the aisle and he is generally in the building as well. His own club uses a different plug and has been using it for years. Made by AMP it resembles the circular plug that is used to connect trailers to cars. We actually had a look at that plug (I did anyway). It turns out to be more expensive and less versatile then Powerpoles. They have adapters to connect to Cinch Jones plugs when needed. They were in Louisville. In fact the loop they were part of was one of the two that got up and running with zero problems by Thursday afternoon.

One thing I have become aware of is that NTRAK is not a democracy. It is simply a set of standards with a newsletter. Join NTRAK and you are paying for a subscription to the newsletter which has not been showing up on any regular basis to most of my club's members. You know as well as I that the total subscription is less than 2500. Much less then the 5 or 6 thousand I had in mind.

Most clubs/individuals decide what standard to use or build to their own rules. BANTRAK has a Onetrak division that specs Atlas code 55 track. That keeps us from joining with other club's Onetrak modules. Those that choose the NTRAK standard can connect to other NTRAK compatible modules. I have never seen a meet where someone was turned away because their wiring was bad. Most times the modules are already clamped down when the problem shows up. Finding a replacement module is usually not possible. A group will just roll up their sleeves and fix the trouble. Everyone comes out the better for it.

I think that you need to face the fact that DCC is here and will be in use on NTRAK layouts whether it's your personal choice or not. Leaving the growing number of DCC people on the sidelines while you continue to play as always simply is not fair to them. If not a majority, DCC use is on the up swing. At the NSE Convention we had two line running DCC and one running DC. I did have the option built in to change over any of the DCC lines to DC if demand required. Demand never required. The majority of visiting runners requested a DCC line.

At some point everyone will need to make some updates to their wiring. CJ's don't last forever and they are getting quite expensive and sometimes a little scarce. Upgrading the wire at the same time as the plug change will still cost half of the cost of replacing 4 pairs of CJ's. Personally, I think the standard should have been phased in with a complete change-over date set in advance. In some respects, that has been accomplished over the past 6 years but without a published schedule. I do believe some advance notice would have been nice especially since they are having many delivery problems with the newsletter. I didn't get to vote either but then I already mentioned NTRAK isn't a democracy.

Martin Myers
President
Baltimore Area NTRAK

 

(Alert: For the EE's in the room, I'll be doing a lot of hand-waving on purpose. This is an attempt at layman-talk. Prepare for sweeping generalizations, gross simplifications, and barely-applicable analogies.)

Up to a certain point, this is still true.... there's "too small", "big enough", and "well, things get complex".

Too small a wire simply won't draw enough current to trip a large booster's circuit breakers because of the resistive drop over a long run. "big enough" wire will fix this. Try sucking enough water through a straw to put out a fire. It just won't work. Use a bigger pipe, and at some point other factors become more important than the pipe diameter, like the smoothness of the bore, the length of the run, the pressure of the water, etc.

What DCESharkman is talking about is a whole 'nother level of complexity, caused by some of the complex interactions that happen when running a high-current AC signal over a long wire. Above a certain minimal size, the wire is big enough that simple resistive losses are overwhelmed by these other factors he's talking about, and the wire size no longer matters as much as the quality of the copper, the frequency and harmonic content of the signal, the length of the run, and a whole host of other things. You're out of basic science and into "engineering voodoo" ... but it's all very, very real.

This stuff doesn't really have much to do with the basic "too much current, shut the booster down" kind of problem. What it DOES is it begins to garble the wave shape of the DCC control signal to the point that the decoder can't "hear" what the command station is "saying". AND, under certain circumstances it can actually cancel the signal out completely...

The twisted wire thing is a good example. Yes, it helps to twist +/- wire pairs that carry AC signals - but only if the twist rate is precisely matched (and controlled) to the frequency band of the signal being carried. Doing it by hand, you stand a good chance of getting more bad side effects than good.

 

Okay what you all have said just convinces me that I was correct all along. First, I said this wiring change was strictly a DCC issue from the get go that involved the mega layouts. The average DCC guy probably doesn't need a power booster and could easily remedy any voltage drop by adding an additional feed just as the analog guys do. Second I said this change in the wire standard will not solve the problem. The mega layouts will still need power boosters. They just won't need as many. So what we have is a problem shared by a small group but the solution involves all of Ntrak. It's akin to killing a flea with a sledgehammer. The small group wants to save money on power boosters by transferring the cost to everyone.

Now contrast the wire size issue with the issue of the CJ plugs. I supported the change to the Powerpoles. I did so because there were real problems with the CJ plugs that affected everyone. There were hard to find. They were expensive.They lacked versatility and they had an uncertain future. They were dinosaurs in other words. No other industry was using them and in light of that to expect they would continue to be manufactured was wishful thinking. So a change was necessary. Unlike the change in wire though, this change would benefit everybody. In addition, not only would the Powerpole connectors be readily available, they would cost less, be more versatile and, because other industries were using them have a better future. The change to Powerpoles was therefore one that benefitted both the DCC people as well as the analog people. As an added benefit the Powerpole connectors had 30% less voltage drop than the CJ plugs. That too would have benefitted everyone. Apparently that 30% was not good enough for DCC people.

So what alternatives were there to the wholesale change in wire standards. Well the obvious one is the DCC people could buy more boosters. After all its a DCC problem then let the DCC people solve their problem on their own. More or less pay your own way rather than placing your ills on all of society. Again bear in mind we are talking of the big mega layouts and large clubs and not the guy at his home layout. Another alternative was to recognize that the Ntrak standard of 18 gauge always was a minimum standard. I compare that to getting a "D"on your report card in school. Yeah, you passed but nothing to be proud of. Most Ntrak clubs I know used 16 gauge wire. In fact, at one time, 16 gauge lamp cord was cheaper than 18 gauge stranded wire. The DCC people could have issued an advisory to all DCC people to avoid the minimum and use a larger wire. There was no solution that would eliminate the problem of the voltage drop. How to minimalize it and how to pay for it were the issues. The issues were decided by a committe that was, in no way, representative of the whole Ntrak group as it was heavily DCC oriented and that decision was to require everyone to pay for the benefit of a smaller group. I said before that they stuffed this down the throats of everyone in Ntrak and people do what people normally do when that occurs. They gag on it. So we have, what may very well become the beginning of the cleaving of Ntrak that I mentioned in my first post. There is talk [and apparently plans as well] for two Ntraks. One is "Ntrak Classic" the other is "Ntrak 2.0" This talk is among a group of DCC people. "Ntrak 2.0 is all DCC and operations oriented. "Ntrak Classic" is all the other [analog DC] people.

 

Maybe its time for 2 sets standards as Inkaneer speaks of.

I dunno what the happy medium would be but,I like the two different styles of NTrak standards.

 

So, if 2.0 sticks in your craw, go with #16 and PowerPoles (Ntrak 1.5). You will be better than the 1974 standard, and a bit shy of the 2011 standard (not quite grandfathered, but sort of an elderly uncle). You won't (or shouldn't) be turned away by being non-compliant, and your chances of being the "weakest link" will be reduced (but not eliminated).

The 12AWG recommendation preceeded my original (2004) PowerPole proposal, but they fit well together and both addressed a common issue.

Remember Reginald Denny.

 

To Ink -

I don't see how you think the wire change was purely for DCC. From what I read here, I took away that the change helps DC more than it helps DCC as over longer runs, the signal loss in DCC is still a factor. Better, larger gauge wire improves operation in both DC and DCC modes. I am still fairly new to NTrak but I can't belive the standard before was lamp cord. Expense of the wire should not the be primary consideration, quality of operations should come first. The changes make both DC and DCC work better. Our clubs setup has 3 boosters and 3 Aristo craft throttles, one each for each line. With the flip of a switch, you can run DC or DCC on any line. We usually only have one line DC as most people in the club have DCC equipment now. It allows more people on the layout at one time. We will have as many as 9 trains running at once when the layout is big enough. We will usually have at least two trains per line at a show. Keep the people entertained.

What exactly is your objection anyhow? Is it cost, the effort to replace the wiring on you module, the difficulty in finding the proper parts?

We are talking an insignificant cost here in the overall scheme of things. People will spend $100 on a loco but won't spend an extra $5 or $10 on good wire to make thier module/layout run better? The buss line on my home layout is going to be Deans Wet Noodle (12 gauge, 1660 stand count wire). It is what I have used for my RC cars and what I will used for my trains too. It was $40 for 25ft so I have $80 in wire just for the bus on my layout. It is probably overkill but I know it will work right. It will probably go on my Ntrak module when I get around to building one because I would rather build beyond the minimum and know my module will not be the weak link.

I'm begining to think it is the american way to do the minimum to get by and not go the extra effort to make things better.