Items labelled "new" on eBay can be very not new. 

For example, I once bought a "new in box" diesel locomotive B unit that was supposed to be powered.  It was in the box for a powered unit and had the shell number of a powered unit.  But, when I receive it, I quickly realized that somebody, at some time, had replaced the mechanism with a dummy mechanism.  it was probably not an attempt at fraud, since it was so easily detected.  It was probably that some previous owner wanted a powered version of the B unit shell that came from the factory with the dummy mechanism, so he bought both powered and unpowered versions and swapped the shells.  Such things happen a lot.  Then, when the owner dies or sells his entire collection to a reseller, the person who is selling these things to us has little knowledge of the history of each item, and maybe not that much working knowledge of the items at all. 

In my case, karma was on my side.  I later bought an "unpowered" B unit and found it to be powered.  Based on a note in a photo giving a decoder address for the "dummy" unit, I suspected that it was powered and informed the seller before I bought it, but she did not change the listing nor up the price.  Was that the "other part" of my previous mis-match? Maybe, maybe not - I'll never really know.  It was 2 different sellers.

Quote from: spookshow on June 05, 2018, 09:17:24 AM
The other way to differentiate the two is the tender coupler - Rapido on the older ones, E-Z Mate on the 2012.

The problem with that advice is that we are talking about buying out-of-production models from some previous owner who may or may not have changed the couplers.  Or, maybe the owner before the previous owner made the change, and the current owner doesn't know about that. 

And, a previous owner may have changed MicroTrains couplers for either Rapidos or E-Z Mates.

Best to look for the DCC wires running between the loco and the tender, if the eBay photos are good enough to even see wires.

Quote from: Len on April 17, 2018, 11:02:54 AM
"Please note that the knuckle height gauge needs to rest on code 80 rail, because its bottom can reach the plastic tie "spikes" on some code 55 rail and raise the gauge up off the rail head, spoiling the proper measurement for coupler height."

A couple of swipes on the 'guide rails' with a 10" flat mill file will take care of that problem, while still letting it work with larger rails.

True enough.  But not really practical unless you always do your coupler work on a piece of track that you have taken the time to modify.  Easier for me to just use a separate piece of Code 80 track when doing coupler work, rather than modify a piece of Code 55 track and then make sure I don't grab an unmodified piece whenever I do coupler work.

No matter what you choose to do about keeping or changing couplers, I suggest that you start with getting a gauge to measure the coupler knuckle center height and the trip pin clearance.  MicroTrains makes a good gauge for that.  Actually two gauges, one with a coupler that is mounted to a cast metal part that sits on the rails and holds the coupler at the NMRA standard height above the rails, and the other gauge is just a flat piece of metal 0.010" thick that sits on top of the rails and the trip pin should pass over it without touching.  Please note that the knuckle height gauge needs to rest on code 80 rail, because its bottom can reach the plastic tie "spikes" on some code 55 rail and raise the gauge up off the rail head, spoiling the proper measurement for coupler height.

It is also necessary to make sure that the couplers are not sticking to one side or the other, nor drooping.  If they are sticking, some dry lubricant squirted into the coupler box can sometimes fix the problem.  Microtrains "Grease-em" is designed for that, but do not be fooled by its name, because it is not actually grease.

Replacing couplers is both expensive and a PITA.  Part of the pain can be traded for expense by purchasing couplers already assembled in their boxes to mount on car bodies, or buying new trucks with the couplers you want already assembled in them.

But, before you go to all that trouble, it pays to take a close look at your track to see if that is really where your problem lies.  If all of your uncoupling issues happen at the same spot(s) on your track, look there for issues that can cause cars to uncouple, particularly if there are some minor issues between a pair of couplers that are otherwise compatible.  Such things as kinks in the rails due to misaligned rail joiners, track sections that are not connected straight, or sharp changes in vertical angle between sections. Most knuckle couplers today can successfully run together.  Atlas couplers are notorious for dropping their pins, which does not cause them to uncouple.  But, those loose pins on the track can cause other issues when they are struck by other cars with other couplers.

Good luck finding a solution that works for you.  Let us know how it is going.

Now I understand - it is a Bachmann loco, but On3.  I was looking at the Bachmann N scale locos while trying to understand your problem.  I guess we both need to start stating scale when writing in the "General" part of this forum.

Terry, I am now really confused.  I also have 2 Moguls, Bachmann Item #s 51756 (B&M #1363) and 51751 (PRR #3234).  Bachmann refers to these as "'N' ALCO 2-6-0 Steam Loco (DCC)".  The tenders on mine have all-wheel pick-up on both the front and rear trucks, just like the Bachmann Spectrum versions of the 2-8-0 and 4-6-0.

But, I notice that there are no drawings on the Bachmann parts website for what I have.  What that site shows for a "2-6-0/2-6-2 Locomotive" is a strange setup where the front truck is all wheel pick-up and the rear truck has wheels that are electrically isolated from the locomotive, with one wheel on each axle insulated from the axle to prevent creating a short circuit between the rails, like any freight car truck with metal wheels.

What you are describing seems to be different from either of these two cases - it has both trucks with wheels that are electrically connected to the axles on one side and insulated on the other, and axle wipers to connect electrically into the mechanism.  And, it is DCC.  To me, that sounds like a Model Power/MRC version of the Mogul, and MP/MDC does call theirs a "Mogul".  So, you may be asking for help on the wrong forum.  Or, at least you need to tell us what manufacturer made the loco you ask about.

For your particular case, it seems like you did solve your own problem by comparing your two locomotives, so things are good.  But for the future, remember that other posters will not be able to help you, and might actually mislead you, if we are misunderstanding what locomotive we are talking about.

Terry, it sounds to me like you have the wrong tender, or tender trucks, or maybe just the tender wheels for Mogul #5.  The DCC Mogul is supposed to have an all-wheel pick-up tender, with 4 brass "ears" that extend up into the tender frame from each side of both trucks.  The tender you describe as having wheels insulated on only one side sounds like an old DC tender to a Prairie, not a DCC tender for a Mogul. But, I am not understanding how that would "plug in" to the Mogul, so it sounds like somebody has switched trucks or switched wheels in the trucks. This is most likely where the short is coming from, but, without knowing exactly what you have in the way of pieces, I can't say exactly how the combination of components is making that short circuit.  Please compare the trucks on the tender that works to the trucks on the tender that does not work, and see if they aren't different.

Nice work, Terry.

Quote from: Yardmaster on March 28, 2018, 11:27:38 AM
Can't tell you exactly - it is momentary. To be on the safe side use a lower voltage (12volts).

There are a lot of old 12 volt wall warts hanging around most homes.  Has anybody successfully use one for a Bachmann turnout power supply? If so, what was its current rating?

Yardmaster (or anybody who has the info), it would help to know what the current draw is for a Bachmann turnout.  And, are they continuously powered or momentarily powered just to change position (direction)?  The Bachmann website says that the turnout control power needs to be 16 volts, and can be either  AC or DC.  Buying a new DC train controller just to use its auxiliary power outputs seems like a waste of money and material.  An old "wall wart" power supply of the proper voltage from a piece of discarded electronics might serve the purpose at less expense and bulk.  Or, even a new 16 volt "wall wart" seems like it would be less expensive and bulky than a DC train control box.  But, we need to know the power (current) requirements for the number of turnouts on a layout.  If the direction switches are always powering the turnout mechanisms, then it will require a bigger power supply than if each direction switch just momentarily sends power to a single turnout only when the switch position is changed (or the turnout itself disconnects the power input after it changes position).

Another possibility is that there is a vertical kink in the track.  This may be caused by putting the tracks on a surface that is not flat (for instance, a lumpy rug, but don't ask how I know that).  It may also be caused by track sections not mating properly, either because they were accidentally misaligned when the sections were put together, or because the track joiners are bent.

The best way to look for this problem is to put something straight along the tops of the rails and looking horizontally for light coming under it at some area.  Do one rail at a time, along both the straight and diverging portions of the track. 

If the "something straight" is made out of metal, don't forget to turn-off power to the rails before you put it on them.

Yes, you can do that to allow you to control the spur power.  It is often done when the spur will be the place where an engine or lighted cars will sit for a long time without being used, such as a enginehouse track or a passenger car yard.

Just recognize that there are a lot of historical implications for the words "block" and "power district" that don't really apply to that situation.  For example, it the days of DC, "blocks" were intended to allow operation of locomotives independently of each other by putting them in different blocks.  So, the voltage and polarity of the tracks was set-up to be controlled independently in each block to control locomotive speed and direction.  With DCC, that type of track parameter control is not necessary to control locomotives independently, so it is not used for different isolated sections of track.

Another aspect of electric supply to a block is whether it has a circuit breaker that is set up to control just that block (or maybe a group of blocks that is not the whole layout).  If so, then that block is a "power district."  A short circuit in a power district causes all of the locomotives in that district to stop, but the locos in other districts (with their own circuit breakers) will keep running.

One place where you do need to control the power to a block is on a "reversing loop", where the track configuration makes a locomotive end-up going in the opposite direction on the same track (loop or wye).  In that case, there will be some point along each of the rails where the DCC power phase (or polarity for DC) will need to change, at an electrically isolated rail joint or gap.  If you do not have at least one isolated joint in each rail of a reversing loop, you will get an immediate short circuit as soon as power is supplied to the track.  But, you really need two gaps in each rail for a reversing loop to work, because a locomotive picks up power with more than one wheel on each rail. So, whenever the locomotive crosses an insulated gap, it will be picking up current from both sides of the joint at the same time.  If the polarity/phase are not the same on both sides of the gap when the locomotive crosses it, there will be a short circuit.  So, the trick is to have two gaps in the rails of a reversing loop that isolates a section of the rails that is longer than your train, or at least the part(s) of your train that pick-up electric power.  The isolated section needs to have a double-pole-double-throw switch set-up to reverse the polarity on that section when it is thrown.  That way, it can be set to have the rails match phase as the train enters one side of the reversing section, and, then while the train is in that section, the phase is reversed with the dpdt switch so that the phase also matches when the train leaves.  That can be done with a manual switch, or, these days, there are special circuit breakers that will reverse the polarity of the rails instantaneously to clear a short circuit (and, if that doesn't clear the short, it then acts like a regular circuit breaker and cuts-off power to the rails).  The track plan posted by the OP in a companion thread does not include a track configuration than makes a reversing loop, so this part of my reply is for others, or for the OP at some later time when he decides to make a more complicated layout.

Direct radio control of locomotives, whether by Bluetooth (which piggy-backs on the technological developments driven by cell phones) or stand-alone radio systems (which are more expensive), require electronics in each locomotive that are not common on the market, today.

While it is true that there are commercial sources for add-on electronic boards to make a regular locomotive work with direct Bluetooth control, that is not something that a beginner in the hobby is typically ready to tackle.  It is similar to the more usual situation of a beginner with a DC locomotive that wants to make it a DCC locomotive by rewiring things and adding the necessary electronics.  For large scale models like S, O, G and larger, there is plenty of room to add things inside, and the parts are large enough to be robust against ham-handed beginners' skills.  With HO, there is usually enough room, but things are getting more fragile and easily broken.  For N, there is often simply not enough room, and there is often breakage of both model details and mechanism unless the hobbyist is both knowledgeable and skilled.  

So, a beginner who wants to run his locomotives via Bluetooth control is limited to what is available with that technology already installed, which is not many at this time.  And, many folks just don't like the interface that a cell phone screen provides for a locomotive throttle, compared to the regular DCC throttles that have real knobs and buttons.  The cell phone interface seems to make the "engineer" spend more time looking at his cell phone than his train, because there is no tactile feedback and it is easy to click on the wrong pseudo-button if you are not looking at the screen.  Some companies are starting to develop dedicated model railroad throttles that have knobs and buttons and use Bluetooth, but those are not cheap or fully developed at this point.  Bluetooth may be the main-stream system in the future, but, for now, it is pretty limiting for a beginner, especially in small scales.

As for running a locomotive on battery power, that too is a technology that works in large scale models but not is small scales.  In theory, it eliminates the whole job of wiring track for power and keeping wheels clean for electrical contacts.  It would stop stalling due to loss of electric contact to the motor.  On the other hand, it will require repeated recharging of the batteries, which may become a nuisance during realistic operating sessions.  And, there is also the problem of Lithium-Ion batteries that can catch fire.

So, from a beginner's standpoint, the choice is really whether to buy just whatever locomotives are available with Bluetooth to run separately from the DCC loco's EZ Command system by using  cell phones as throttles, or to buy a better DCC command station and additional throttles that connect to it.

Remember, the EZ Command DCC set-up can already run multiple trains at the same time, as I described before,  BUT, it is inconvenient to do it that way because there is really only one throttle that is integral with the command station, and you must keep switching that between locomotives to control changes for one at a time while all are running.  Using Bluetooth control does not change that if you are using only one cell phone for a throttle.  

And things might get really complicated if that cell phone is also still your telephone and calendar, and, while running one or more trains, you get a telephone call, a calendar reminder, or even an OS upgrade.  So, most folks use old, deactivated cell phones for their Bluetooth throttles if they are really into that part of the hobby.  For just running any old train around a circle, none of that is much concern, but the OP of this thread seems to be thinking beyond that.

(I don't have any of these and have no interest in getting any, so I am no expert - somebody should correct me if I am wrong on this.)  I think the EZ App from Bachmann requires a "decoder" in each loco that is made to receive Bluetooth radio frequency signals through the air instead of DCC signals through the rails.  That is different from other apps that require a Bluetooth receiver that connects to a command station, so that you can use your cell phone as a throttle to control any DCC equipped loco.  So, your EZ App can only control the locos that Bachmann provides with these particular Bluetooth decoders, not other locos from other manufacturers or even other Bachmann locos that have regular DCC decoders. 

Other manufacturers that make more sophisticated DCC command stations that have radio control (add-on) features are also now working on adding Bluetooth control add-ons that essentially mimic their regular radio control systems, except that you can use cell phones as throttles instead of having to buy radio-equipped throttles that are particular to the manufacturer's radio control system.  Those are a lot more versatile than the Bachmann EZ App and the locos specific to it.

First, "gaps" are just one type of "insulated joint" so far as track wiring is concerned.  You are right that plastic rail joiners are true "insulated joints."  They both join the rails together physically and isolate them electrically.  By design, they actually prevent the rails from moving together by putting a thin plastic material between the rails.  They are most commonly used with sectional track as the sections are joined together.

On the other hand, "gaps" are more commonly used with long pieces of "flex track" that is laid (instead of many pre-formed sections of track) and cut to fit.  Gaps are usually just that, cuts in the rails wherever an electrical isolation is needed.  But, layouts have a tendency to expand and contract as the temperature and humidity change, so rails tend to slide a bit, and can close a gap that is not filled with an insulator, causing short circuits.  So, many people put a bit of plastic in the gaps they cut and then file it to the shape of the rails so that it is not noticed.

Switch (turnout) frog isolation is a lot more difficult to explain because there are so many different types of construction on the market.  Basically, there are the pre-DCC designs that often just use plastic frogs with the conducting rails coming very close together so that electrical contact with wheels is not lost for very far.  They were fine when used with DC power, even though the often created short-duration short circuits as extra-wide metal wheels passed over them, because DC power systems are not so sensitive to shorts as are DCC power systems. The Atlas code 80 turnouts are one example of this type of construction.  Turnouts designed for DCC have frogs that are either larger plastic sections that keep the out-of-phase rails farther apart, or frogs that are made out of metal and electrically isolated from both rails.  The idea with the isolated metal frogs is that they can be set up to be provided with the proper phase of power with an electrical switch that works in conjunction with the movement of the turnout. This allows locos to go through the turnouts very slowly without stalling for lack of power at any point. There are some sectional track products like Kato that have this already set-up for you, and others like Atlas code 55 track where there are just attachment points for you to use to electrically power the frog with a wire that you need to connect to an electrical switch that you provide and set-up yourself.