Phil S

If you run the loco on dc, via the decoder, you should be able to measure the current the motor is taking - and as you add the load it will increase.. if you have the motor spec you should be able to remain under its limit .... don't forget to allow for an incline or training load

Does the rolling road come with an interference suppression capacitor fitted by Hornby ??? If so - remove it for dcc use !!!!!! I don't recall one on mine, but that was bought many yearsago). As the 9F ALSO has tender pickups - on both rails - it does not need the rolling wheelsets to provde power - only to let the loco wheels revolve - Do you have a meter to check that (with no power applied) there is no resistance from the controller to the rolling road on each wire) and that WITH power - the voltage across the track measures the same as at the controller (whatever your meter shows -it may not be te correct value with dcc,but they shouldstillshow the SAMEvalue - on the AC Voltage range. Does it work in NON-programming mode - ie so you can leave it test running for half an hour ???

On the Continent - as that area to the east of the UK was once known - 2-rail has to compete against '3rail' (ie centre stud) contact from Marklin and they have Mfx(R( which does all that Railcom /+ does - including automatically allocating identifying a newly added loco and allocating its buttons ... the advantage of a single company rather than competitive committee approach. Therefore there is an established threshold of features to compete against in the 2-rail v '3-rail' market. Most Marklin, and all competitors 3-rail versions of locos come ready equipped with a decoder (not necessarily Mfx compatible ...and called M4 when not in Marklin product) .... as the decoder provides the electronic interface to the ac/3-rail. (ESU makes multi-standard locos: 2/3 rail with the user fitting the central shoe if desired - instead of having to stock 2 rail and 3 rail versions.) . For my loft layout - where I have no isolated sections for the purpose of Block/tracking, I have Hector IR detectors (as a separate system to the track dcc) and this is supplemented by RFid tags being read on the exits from any area where train formation is expected to change - ie the storage area and terminal stations. However, for our (trans)portable H0 layout I intend using Railcom on 1 or 2 boards - feeding via the Digikeijs modules - but otherwise retain the optical detection for tracking movement... its predecessor layout was used as my test bed for the Hectors intended for the loft layout ... and I miss the tracking display on the current H0 layout ! ... as Ian suggests ... you miss a feature once you have (successfully) used it 8-)

If the Elite can be used with the Rail master ( or does it become the Rail master is used with the Elite ? ...with a redundant E-link??? ) you should also find you can use other Xpressnet-based handsets as additional controllers ... Particularly if you wish to move away from the console position. Obviously the Select will plug in as an extra handset .....but so should a (cabled) multimaus and some others. {(I don't have an elite, but have used a select as an extra handset on a multimaus based system ...the advantage of Xpressnet compatibilities.))

Marklin-LGB, Gaugemaster, and a number of other firms including Horsemann aiming their products at the larger scales 0 and G all offer 5A dc analogue controllers (and the ZTC511 could also be used as a 5A Analogue controller).... some single USA diesels could easily take 5A before adding a garden railway gradient or multiple heading. Also, ohms law applies equally to small and large, ac, dc, or dcc .... current may not go 'only' where you want it ... it will take any easy path that presents itself. Acknowledging that ' faults occur ' and handling/ designing for them appropriately is the beginning of safe electrics. Whilst you may have a very low mean current (only occasional train(s) moving, your wiring needs to match the current which COULD flow ... the normal maximum = continuous heat dissipation, and the overload tripping) current HOPEFULLY has minimal time to dissipate much heat - PROVIDED whatever overload protection acts sufficiently quickly. Here, admittedly, dcc controllers usually set an example of FAST CUT OUT ... but also a predictable cutout: I am just reminded of our old school physics lab with large Griffin+George 'lab' power supply for the bench terminals ..... IN winter, a large screwdriver held across the terminals on a bench was insufficient to trip the power supply ... because it was a thermal cut out and the lab was rather cold (the radiators were panels in the ceiling A year ago, for one of our portable layouts which uses multiple power supplies and busses, I added manually-resettable circuit breakers of appropriate ratings to protect against (OTHERWISE UNMONITORED) faults in those circuits, and also decided to split my layout lighting 12Vdc bus into 2, as I measured the 6A 12V power supply as running at almost its full 6A ...no room for extra building lights !..... and my spare power supplies were only 5A... ie not usable as spares. One reason I recommend people have a multimeter, and also measure the current their layout is normally taking. Small digital readout modules for volts and amps are available cheaply on Ebay (0-30Vdc) ... and can be installed to look like a digital clock.

NOW APPLY A SHORT CIRCUIT AT ANY PART and see if your expectations are met, or one route is taking more current - because it is the shorter circuit And don't forget, that with a 5A NORMAL MAXIMUM supply - that s NOT a tripping current but would/could flow indefinitely causing heating..... Then see what the (hopefully short duration) short circuit current is. The design premise is WRONG - ...and if used, a lower output controller / circuit breaker should be used to ENSURE the problem CANNOT occur in a fault condition

The above statememt is a falicy: IF your command station or booster OUTPUT is CAPABLE of 5_Amps then ALL parts of your circuitry MUST (be of low enough resistance in the overall loop) to let (more than ) 5 Amps to flow ... Whatever it takes to trip the short circuit protection!! ... Or your protection is inadequate. Having said that important safety point, there are ways of reducing the needed current: 1/ PSX or similar circuit breakers set to a lower value eg 2 Amps....BEYOND the PSX circuitry ( including all track droppers points etc) need only take a bit over 2 Amps. 2/ Use a controller with a lower maximum output ... Such as some 'starter' types, or with a 3 Àmp limit ......these perhaps being better/safer options for an existing sectionalised analogue layout whiçh anticipated only about 1 Amp per loco or section. Some controllers can set their own lower maximum current too. NOT to check that BOTH the tripping current can flow momentarily AND the MAXIMUM can flow CONTINUOUSLY through all parts of the layout exposed to it is the equivalent of leaving 13 Amp fuses in plugs 'protecting' 5 Watt LED lamps .. i.e. no protect at all. (Then all you would need is a steel wool tree to fall on the line and start a fire)

I am in the process of converting several Marklin locomotives to 2-rail DC from either Analogue AC 3-rail, Delta or M80 digital periods In each case, one of the 2 motor brushes is made from a copper wire mesh wound into a roll - the other is carbon/graphite as normal. Does anyone know why - presumably optimal for ac motors - ONE brush is made this way ??? ================================================================================================================== For anyone interested in converting Marklin 3-rail/stud to 2-rail dc/dcc... my experiment is as follows... FYI - Once the diameter of the motor windings is measured, the identification of which ESU Magnet conversion kit to use is quite simple. The other choice is between a FLAT commutator or a 'DRUM' (cylindrical) commutator. I was prompted to progress these conversions when Marklin announced new back-conversion kits earlier this year, with multiple protocol decoders, and 5-pole replacement coils ......but I have actually opted for the simpler magnet change and retaining the original 3-coils. As observed by my friendly dealer - old Marklin stock may be well soezed up as the old grease turns to solid glue - that was the case with the Zeppelin Aerotrain - both drive and propeller motors totally siezed at first. ! The other parts of the conversion process for me are: Fitting a DCC decoder and LEDs instead of bulb lighting - simple with plenty of space once the Solenoid reversing switch has been removed - and existing decoder - ( Of 2 'identical' 2-6-2T locos - 1 had delta and a permanent magnet already, the other had a coil motor. one Electric loco in a Marklin Digital Box was totally analogue - no decoder fitted - despite the 'cutaway impression' of one on the box ...generic boxes !?? of course, the other major problem is insulating the wheels and then replacing the pickups).... The driving axles of most locos I am converting is 2.5mm - but others may be 2mm. The first ( a Swedish D type) has continuous support through the chassis - others may only provide support immediately behind each wheel. My 1st choice of replacement axle is ABS Rod ... and this is stiff enough with the continuously supported axle. Free running with graphite lubricant. I also have 2.5mm tube in which to insert a metal (steel) rod to try a 'stiffer' version. Option 2 The alternative being to open out the wheel centres on 1 side, for a sleeve fitting over the existing 2.5mm steel axle ... option 3 of course, a plastic axle won't have the life of the steel axle - but it will serve as a low cost starter to see how the conversions work. {and a nylon washer on the noon-gear-train side to ensure the wheels stay away from the metal chassis) Other niceties to consider: Coarse wheel standards ... close on some to touching the chairs on Code 83 (no problem on Code 100 track) and ensuring that couplings or other parts which come into contact with another vehicle are insulated from track and motor / electronics Replacing bulbs with pre-wired SMD LEDS is the final step.

It might be useful if you listed all of the outputs that this smoky box provided - and with what current ratings !!! Suitable advice might then be possibe Some of your downstream devices may require ac; others may be 'universal' ... in which case a DC output SMPS will be available. SMPS are also lighter in weight than 50Hz/60Hz transformers - as well as being more energy efficient, and cheaper to buy. In any replacement 'box' ( I recommend plastic boxes from a Really Useful box company - to CARRY the power supplies in - NOT to USE them in 8-) consider having suitable protection and switches for EACH of the power supplies ... and keeping them separate allows individual replacement in the event of a fault - and individual PAT testing.

Even though a controller may 'know' which way the command was sent eg left or right,it does not know WHAT the device was - whether a solenoid point motor or a colour light signal,level crossing lights possibly with barrier,or a solenoid uncoupler .... it must always send the fresh command ... and my initial note was that the track signal will send more than 1 instance of the command ... about 15 I counted with a multimaus ... so any software based onmonitoring the dcc signal needs to understand this. [the graphic on a multimaus handset is repeated on any device showing that accessory number - vdu smartphone tablet or other multimaus.]

I don't know about the Powercab, but Multimaus sends a point command as part of the track signal (ie dcc not Xpressnet) about 15 times .. this can be observed with any DCC sniffer reading the track dcc data .... a method I would recommend as results may vary between software versions and reading it gives certainty. The multimaus triggered command is repeated even longer if held down ( for example when it is used for an uncoupler) From MERG discussions some years ago wrt to their accessory decoders ....Lenz sends another commandat the end of the 'time'. ... someone else may recall more on these variations. Best not tocommit a design to aspftware feature which may change without notice ?

ALSO a CAUTION against using #an old controller# to test or drive a loco ONCE A DECODER HAS BEEN FITTED .... Old-fashioned, even if 'much cherished' pre-electonic era controllers such as H&M Duettes, Clippers, Safety Minors, Tri-ang Controllers - whether with Vari-wave, Half-wave and full-wave switches OR NOT are UNSUITABLE to use with a dcc-fitted loco, and the loco will often not run correctly, only one way, or even expire the decoder BECAUSE these old controllers simply rectified [after the voltage reducing transformer] the 50Hz mains sinewave - and pass it to the outputs 'labelled 12Volts dc' at variable level .... outputting up to 28V peak voltage at 100 pulses a second .... falling to 0 100x a second too ...causing the decoder's processor to become confused and continually having to restart (100x a second!)...getting nowhere ... heating the motor and decoder, and often unable to detect which direction it should run. The simplest test of any loco -fitted or unfitted- is to place it on a separate piece of track, and touch a 9V battery to the rails. Any analogue,or DCC_fitted loco in the default setting** should then run.. whatever its loco address ... rotate battery and repeat. The loco should go forward when the Right hand rail is the +ve, and in reverse when it is negative (except for LGB G-scale) **some users disable DC/analogue running due to problems when power is first applied with some controllers ... this is not a good idea for fault finding diagnosis ! DECODER FITTED locos, when used on 'analogue' need a controller with a REGULATED OUTPUT VOLTAGE which is 'smooth' .... it can still be pulsed... but at high frequency ...NOT 50 or 100Hz ... and this is how some/many Gaugemaster controllers operate, as well as those from other makes (it is more energy efficient than actually varying the voltage ... and EC regulations now require that all train set power supplies (for sale) use SMPS power supplies and not 'conventional 50Hz transformers'. 'DCC READY' does NOT mean 'Ready to run on dcc track' .... it means, as stated before, that it has a socket for you to 'easily add' a decoder of your choice [it means the internal wiring is suitable for adding a decoder]. Only DCC FITTED and DCC SOUND or similar labels come pre-fitted from the factory. If a shop adds a decoder for you - the labels won't change ... but the cost will have increased 8-) THE OTHER SCENARIO - whereby a dcc-fitted loco will not run on DCC is that the number is different to that you expect BY DEFAULT decoders usually come with Address = 3 ...so this address should be tried first. BUT some manufacturers, or retailers, when Pre/fitting a decoder may also alter the default value - IF SO this is usually stated on a label somewhere. If in doubt - the first thing to do to get a response is to PROGRAM it to '3' or any preferred number. Especially if tried on an 'old controller' then the decoder might benefit from a RESET .... if a decoder WAS fitted, then the locoshould have been supplied with a MANUAL which lists how to RESET the decoder (look around 'CV' 7 or 8, for something about writing '8' to CV8 ... but it could be 2, 6, 33, 55, 77 and to CV7 or8 depending on the make -but CV8 to 8 is most common

No Roco Controller will allow an analogue loco to run - as this is not a recommended practice, and is a policy followed by many,but not all, controller manufacturers. An 'unfitted' (analogue) loco will BUZZ and get warm on a dcc track. Did the invoice for the loco include a decoder or state that it had one pre-fitted ??? 'DCC Ready' does NOT MEAN it has a decoder fitted ... it is a confusing phrase meaning that the loco has a SOCKET for a decoder built-in - but you have to open up the loco and fit the appropriate type of decoder (There are many different fittings available depending on how many features may be available eg 6 or 8 21, 22 18 ...... 6 pin decoders are used in many small 00/H0 locos and N gauge - 2 pins for track connection, 2 for motor, and 2 for Fwd/Rev lights. 8 pin (2 x 4 in shape) is the most common and as well as 2 track and 2 motor has a +ve pin and upto 3 functions Current ratings and other features vary between decoders - as does cost. DCC FITTED or DCC SOUND identifies a loco which HAS a decoder fitted at the factory.

The current draw to run at the same speed will increase if the supply voltage is reduced ... ohms law and P=IV It is therefore more efficient to use a 16Vdcc track voltage than 12V ... as this is compensated for, at 16V, by needing only 75% of the pulse width at 12V ... less heat is dissipated in the decoder.*** HOWEVER - when a short occurs, the higher originating voltage would result in a higher track current - up to the limit of the power supply/protection level. ...which in turn makes short detection easier. I fully agree with earlier comments about the risk/probability of the plug shorting by being pushed down 'too far' - and the need for insulation beneath the socket .... Roco use a piece of plastic in many cases . A thin piece of plasticard may be more durable than the insultating tape alone. Unfortunately, WHICH pins get shorted is not so predictable - it could be the pickup/track pins [shorting the controller only] or the motor pins [ possibly damaging the decoder], or even a function, or combination of the above.. which may bypass any protection in the decoder itself. The [ Heljan ] locos current draw will be most when stationary ['stall current'] - just starting (and a Lenz decoder is usually rated for a higher current for 3 seconds, BUT any load hauling, gradient or curved track will increase the load from that of a simple test on level track with a light engine. More margin/headroom can be provided by replacing the bulbs with LEDs and resistors. I have recently 'successfully' tested TTS decoders in a Heljan diesel: by adding a 10 ohm resistor in SERIES with the motor - I have ensured that the motor current CANNOT exceed the current rating of the (TTS) decoder (again ohms law and a multimeter check). This will reduce the maximum speed and power of the loco in use - slightly. But the unlimited top speed (no CV5) of the TTS decoder is more than required [with my 16Vdcc track voltage - Roco 18Vdc smps ] ... but I have yet to test the result on my 2%-4% gradient with a 'full load' behind. ...but that would be no more than 5-6 coaches and 600mm radius curves in my case. ***Back in Zero-1 days, when the track power was NOT full wave rectified (so may not apply if ZTC Zero-1 decoders are used) the 4A current limit could be reached 'easily' if all the locos were travelling in the same direction, but possibly twice as many locos could be running if equal numbers were running in each direction ... because each direction had its OWN power cycle time-slot.... Locos in 1 direction would ALL be taking power at the END of that direction's power cycle (because higher speeds turned the thyrister or Triac on early in the time-slot). One of the benefits / assumptions of DCC decoders is that they full-wave rectify the track signal, and then pulse-drive the motors at their own (decoder controlled) rate ... so hopefully different decoders even out their current demand on the controller ... maximising the number of locos able to run within the limit. Early decoder designs (including Zero-1's) also used a low frequency (often mains-related) pulse rate for motor drive .. resulting in large heavy pulses, whereas modern decoders tend to use high frequency pulse rates for motor drives giving smoother, more even control and current demand. .... I recommend monitoring the system current = often displayed by advanced controllers/handsets/smartphones ... to see what quiescent current is taken by other decoders, and then the loco motor as it traverses the layout.

AccAccidentalcopy from somewhere unrelated ....so deleted to avoid confusion

The original question was by wab64 and asked about the POWER BUS. ( and this follows NMRA standards for nmra DCC products ) The later query by das.... Concerns something NOT covered by NMRA standards ...the connection ( if they are separated) between the Users Throttle or Hand Controller ( or coñsole ) and the 'central unit' where the NMRA DCC format signal is output to the track+accessories (+ possibly programming track) and possibly a 'low level' version to feed / control / synchronise another amplifier or Booster. The format and arrangement of this 'control' bus varies between manufacturers ....although many use the same standards/protocols allowing interchangeability, others are unique. .... The plug/socket design may appear similar or not .... And maybe incompatible. Compatible and well hnown interchangeable standards are Lenz's Expressnet® .... Used àlso by Roco , Hornby, Ztc , Digíkeijs and more .... And Digitax's Loconet® also used by Fleischmann and others. .,and therefore the Roco/Fleischman Z21 offers both Loconet and Expressnet (Roconet) WIRELESS links are also available .... 'Previously' as expensive unique designs having to meet EU or USA standards (different !) But now, with the increased uße of WiFi ....such as the Roco/Fleischman WLAN multimaus or Smartphone. ... Cheaper than many cabled handsets Massoth use their own Dimax protocol but have adapters to Expressnet.. Roco's implementation with their cabled multimaus and amplifier has the MASTER handset permanently plugged in to the Amplifier ...it is the source of the DCC signal which is amp!ified for the track, and passed on to Any boosters ( in a passive loop-through) with the DCC signal on 2 of the 6 wires. The Control signal (roconet/Expressnet) is also generatéd in whichever handset-is-plugged-into-the-master-socket, and uses the RS 485? Standard and can have multi-drops but is basically ... Extended as needed around a layout ( 4 wires used in the 6pin plug: +/- añd data +/- ). Y- adapters can be used to 'split or branch-off the cable to any handset as needed..... Not all need to be plugged in, and any termination is inside the handset. 32 handsets maybe used. All these additional handsets are on a cable run plugged into the 'slave’ socket. Note that whichever handset is plugged into the master socket holds the active memory of points/signals/speeds etc. Each handset has its own library of 64 named locomotives ...which can be copied between handsets. With their later MultiCentrale Pro and then Z21/z21 controllers .... Like Lenz, the computer is 'in the box'... And all controller busses are 'slaves' as above.... Using 4 of the 6 wires in the leads. ..... Or wireless (via a WiFi hub with Z21 and Digikeijs 5000. It is not necessary to unplug and replug as you go around ..... Because you can simply pickup another handset, and 'takeover' a loco from a less convenient handset if you so wish. Of course, with wireless handsets you can simply walk around too !!! ( essential in a garden ! ) Loconet is network/ packet based and plugs as you would 'network' devices.

As a layout gets larger, it can be more convenient; for fault-finding, to have isolatable sections of track - but not necessarily (or likely) to be in the same places that 'analogue' sections would have been: their choice of position and extent is to make the job of finding where a problem is easier. Eg - either end of a tunnel section - so that if there is a 'hidden short' - you be certain whether you need to gain access to the tunnel, or not 8-) [ Back in the days of Zero-1, when my loft layout was a single electrical section, I had a short 'somewhere': luckily only 1 train had been moving ... through a tunnel ... I ended up lifting the track at either end to confirm the short was in the tunnel ... then found a single strand of wire laying in the ballast - presumably disturbed by the passing train. ] Switches / Easily removed joiners in the power bus (I now use WAGO lever connectors for tool-free access) , with isolated track sections would allow faults to be found more easily, or to keep other parts running until it is corrected. A short CAN be located on a large single-circuit loop with a multimeter ... it is the point of lowest resistance !! .... but it can take some finding, and a lot of stock may have to be removed ... if sections cannot be isolated easily. Therefore my current loft layout is broken into 4 sections: Storage, Left, Main, and Right scenic sections ..... and within the station, the sidings are 1 isolatable block - making fault location easy (and 'faults' DO occur in real life). So, confirming the previous answer: the loop does NOT HAVE TO BE broken ...BUT suitable breaks are a USEFUL AID to fault-location; keeping trains running elsewhere (I also use PSX's for the different sections). Other factors are (via gauge): the RAIL SIZE and material. N gauge track in Nickel silver has quite a 'high' resistance.... 00 track codes 70 > 83 > 100 less so, but LGB G Scale track is brass and code 332 ... much larger AND more conductive ... my 125m of garden track has 0.5ohm resistance (and is 1 electrical section [ but with parallel multiple bus feeds too ] ) , and our portable G Scale layouts ( upto 17m long) rely ONLY on track connection (using Massoth Screwed Rail clamps) ... so the need for and frequency of 'dropper wires' depends heavily on the rails used... it is understandable that N gauge users wire every piece (apparently). Personally, for 00/H0 code 83, I find feeds every metre or so (with Rocoline ballasted sectional track in 200mm pieces) is perfectly okay 8-) I also parallel-feed adjacent tracks. (But then I don't pour insulating glue on my tracks to seep into fishplates, isolating them) But a final note: even with 0.5ohms total resistance through the track, my garden line had poor pickup recently .... the dirt from nearby 'groundworks' had 'invisibly' coated the track surface and been baked on hard by the sun !! ... it took a lot of track cleaning to remove this insulating layer 8-) ... clean track is important, even with stay-alives. Think 'sections' for ease of fault location, and to keep other trains running ... not analogue thinking or for erroneous concerns about 'loops' ... layouts aren't large enough for it to be a problem. [ But admittedly, after experience with Zero-1 as I added the last of 30 accessory modules... I had to check the waveform shape with a 'scope to maintain the signal quality... by removing surplus capacitors across each (zero-1 module) input ] Whilst some people advocate snubbers or similar addons .... often without having checked the waveform on an oscilloscope... I would suggest the problem in that case is more likely to be the controller output drive capability ( Eg the Hornby Select rings heavily on open-circuit track... but this is damped by just a few decoders on the track. By contrast my Roco and Massoth controllers maintain a good waveform at all times).

Long address [programming on a Multiumaus is extremely easy ! (and fast, without wasting time on readback - with basic amplifier) 1/ IN NON PROGRAMMING ( operational) MODE - enter the 4 digit loco number you WANT ie L= xxxx 2/ Enter Programming Mode: Choose CV [29 ] [OK] and then your preferred value ( I use 6 or 38 as I keep analogue active ) 3/ 'Cursor sideways' to 'LONG' address [OK] .. whilst it will briefly show 17,18 it will then OFFER your 4 digit number entered at step 1 (If not - now is the time to type in your desired 4 digits) - then press enter (OK) 4/ WAIT a short time while it completes programming - watch for the 2 kicks from the motor to show both 17 and 18 have been written. 5/ Exit from Programming ((stop,stop)) and test on the number already sitting selected as the loco address. Easy. IF you use named locos, then an extra step to switch between NAMED (Library of 64 locos, with SHORT OR LONG ADDRESSES) which also remembers whether that device/decoder needed 14 28 or 128 steps (Eg ROCO CRANE uses 14 steps) is needed, and then a NEW entry in the library to choose the loco number, speed, and name (5, or 10 scrolling characters with Z21) I prefer to have a separated test track connected to a separate Multimaus and basic amplifier - for easy programming without stopping any trains on the main layout, and without the delay of reading an old value ...I'm more interested in the value I enter 8-) Using a test track with certain other controllers using separate program outputs which CANNOT be used for testing the result (such as the Massoth Dimax) require a switch to be able to both Test and Program a loco on a test track/rollers ... which can be cumbersome with heavy G Scale locos ! [ An additional resistor may be required when programming G Sclae locos on controllers aimed at the 'general' standard of current draw during programming]

This would suggest a problem with the connecting JST plug and socket connecting the loco to the tender - if the tender is lifted off the track ( eg a placed on a sheet of insulating paper - and no Lenz decoder with ISP is involved 8-) ) the loco pickups should still power the sounds and when speed>0 (after any start up delay which can be 7 seconds) move the driving wheels. When the 2 parts are separated, a meter should allow you to check continuity from EACH wheel to an appropriate pin on the plug/socket (use a resistor, or other thin component lead to insert into the female part to make contact) it would be worth checking ALL wheels. The other 2 plug/socket connections are, of course, the motor - and so, on the loco side, the separated loco should show about 20 ohms resistance. Another possibility to eliminate is a short to chassis by a wheel on a curve or similar - this would not damage the decoder, but momentarily remove its power .... and with a (sound on ) restart, they can be a start up delay before moving off (ESU or TTS decoders ...ESU in this case as an XS suffix? . A cure if this occurs might be a piece of black insulating tape on the chassis.

When I used a small (G scale portable) shunting puzzle layout with Servo-controlled points, we experienced the large current demand of all the servos starting up (or after any 'emergency stop' removing track power) ... these were being driven from just 2off 4 output Bachmann/ESU ServoPilots. One of the reasons we reverted that layout to conventional LGB 1/2 turn motors. On another of our portable layouts, I also decided to add a ' conventional ' resettable fuse on the accessory bus - as it could otherwise be fed 3-5A continuously when it rarely used 1 Amp ( in this case all point motors were now driven from TrainTech CDU point modules - so only controlled current flow, BUT I also added some other 'power consumers' on the accessory bus ... and it was sensible to provide some degree of protection to the rest of the layout (ie keeping trains running on the track busses) if there was any fault on the accessory bus - they cost very little, and are relatively 'slow acting' - and as they are a push-button reset, they cannot be ignored in the event of a fault. When responding about loco decoder problems, I usually suggest the use of a multimeter - and here too, I would recommend an ammeter to monitor how much current is being drawn from the central unit ... in many cases, this is available on a menu screen of the controller or central unit (eg ZTC511, Roco MCP or Z21/+multimaus, Massoth Dimax and many more). I use Rrampmeters on my loft layout (readable across the room). My recollection from Zero-1 days is of Peco (original type) point motors taking 6A and a 'larger' H&M taking 'only' 4 Amps... for example .... Servos take most power when changing position. On the PSX's - do double check the same phase is being cut by each one - otherwise a fault at a boundary between 2 PSXs on the track can bypass the cut-out ... using their 'loop through' connections can make this error more likely, from the way they are arranged, as I recall ?? .... if in doubt use the AR version which isolates both rails.

As Keith suggested - an Auto reverser is NOT required for this kind of trackplan: The tracks at A and C onto the triangle should be isolated on BOTH rails. POWER to B is changed via a DPDT Relay (OR extra contacts on the switch controlling the points A and C together**) (**this may depend on what type of point motor you are using, or whether you use DCC to control the points) Uhlenbrock make small accessory decoders with changeover relays - 2 models 1 with 2 independent SPDT relays and 2 addresses (any address - not compulsory to be adjacent - learnt by push button) the other with a paired /DPDT relay and 1 address. I use this technique [at EACH END of a helix connecting 2 levels] - and at each entry/exit I have such a triangle - the POINTS determine which way the power NEEDS to be applied .... so the relay uses the same address, and switches to match. (In my case, they are each on separate boards - but if on the same board, you may be able to physically combine the switching.)

'Multiple PSX's would be in parallel not series !!! Compare to your household mains fuse box/breakers - incoming 100A or so, 32A 16A and 5A circuits for various parts IN PARALLEL ... ie when 1 trips, the others are still working. So with 1 central unit ---------dcc output---------------------------------------------------------------------------------------- Accessories...... ! ! ! PSX A PSX B PSX C ! ! ! TRACK A TRACK B TRACK C Example: 3A-5A from central unit 1-2A for each PSX (ie less than central unit Accessories might include your programming track - or this can be a separate feed - it MUST NOT go via a PSX PSXs will automatically attempt to reset every 2 seconds .... useful when the 'reset' button is not near the derailement PSXs ONLY break 1 rail connecttion: USE PSX-AR if you want or need to break BOTH RAILS connections It can be useful to position the 'diagnostic LEDs' where they can be seen easily - not hidden beneath the layout.

I think the sprung contacts rely on the screws holding the chassis in place to make good contact ... certainly on the other diesel designs which used this method. Newer production gas changed to plug and socket connections ... and when i m8dify older types i replace the connections with jst micro plugs and sockets ( as now used for tender connectipns)

It looks to be very related to where it is on the track ... it repeats on the 2nd circuit at the same place. Therefore it is likely to be a pickup/short related issue.... First try running JUST the leading powered car ... that will eliminate any problem caused by wheels on the following coaches causing a problem. Then also try running the power car in nothing directions just to verify the same/similar problems ocuring. You have no need for any boosting to run a single HST. .. even with the other locos (stationary) on the layout ... so try reverting to the basic dcc controller. If you have a multimeter ( if not, why not... get one before the show!) Check for continuity of track voltages. .. even if the meter gives inaccurate readings on ac volts ...they will still be food for comparison around the layout... and with the controller disconnected measure resistance around the track ...back at the controllers position and for the problem areas. (With and without stock)

You still do not appear to understand the situation that the USERS** address in DCC accessories is NOT DEFINED (adequately) by the NMRA 'standard' **address appearing on the controller screen which may not be the same as the electronic dcc-address sent to the decoder for reasons explained previously This is not a problem experienced within Marklin Mfx because that is a '1-company' design ...dcc was originally designed by Lenz and adopted by the NMRA with some slight differences ....including whether counting starts from 0 or 1. If you read a Lenz decoder manual for example... bits are from 0 to 7 But others describe the same values as being bits 1 to 8. The same interpretation/translation confusion affects accessory addressing. There is no rule 2 high dictates how the manufacturer identifies the accessory on the controller...devices with 4 pairs of outputs ( or 8 x 1) were assumed So some are based as ' module' and then 'output' then on/offside or left/right .... and Roco v Lenz are the opposite way on that and both use expressnet !!!!! Have you TESTED the signal you gave configured for 5 on the Marklin dcc protocol (as per it's manual ) on the Lenz System to see if it responds 'AS IF' it had been programmed to EITHER 1 or 9 .... ie 4 lower or higher than you expect from the Marklin dcc setting ????? Please come back after you have made this test ... then if it still does identify the problem we can think of other reasons