bertiedog

Dan

 

You may want to look here for some controller ideas (and plenty of other info to distract you!):

 

http://home.cogeco.c...rcuitIndex.html

 

But to answer your question - I built this a few years ago:

 

http://users.rcn.com...tcl/ccartcl.htm

 

which ticks most of your boxes and was used extensively on an American HO modular club layout, hence had to cope with a wide variety of mechanisms - old and new.

 

The only changes I made were to the momentum resistor values (as suggested in the text) as we found for our purposes there was too much delay/momentum; you could practically go off and make a cup of tea

before some locos really got going! Hence suggest fine tuning values to suit. Controller worked well and has now been passed on as we graduated to DCC....

 

John

The circuit is fairly straightforward, although for non electronics builders a bit short of some basics like the power connections to it! ..you have to assume a lot, .......also the UK 50 hz mains frequency difference from 60hz in the States may explain the slower responses to the commands, meaning lower some of the trimming values ,as you found, to compensate.

All parts are available easily and not costly, although the reversing relay adds a bit. Substitute transistors,(properly chosen), would work, nothing is too critical.

It would be a very good general purpose circuit, and removes most risk from pulses noise and potential heating effects.

Stephen.

There are lots of suitable designs on the net, but as you say how do you know what they really do?

I know, as an electrical engineer, but even then the circuits may not work as expected, so it needs recommendation, and the best course is to join the MERG group, who are a club, shop, group of enthusiasts etc, and have the experience to say what works and what does not.

Your requirement is for control of older "type" motors, none the worst for that, straight DC, with feedback may be the best, with variable pulse available in a switchable form. It would be the same for an all Mashima fleet, they just have lower draw on current.

Feedback works where a fleet are basically the same motors, otherwise it has got to be in some way adjustable. Double motored locos cause problems with feedback and don't work with the set-up.

The best control for low speeds are variable mark space CV (constant voltage) controllers, but if the motors are 3 pole and 5 pole on the same layout there may be differences, and such controllers are able to make the motors hum due to the pulses.

The next best are feedback controllers, which can be CV mark space types or pure DC, or a mixture, a circuit that senses the load and back EMF, trying to maintain a constant current drain, again when pulses are used the motor may hum at low speeds.

But after all the extras are removed a pure DC supply is able to run any type of motor without hum, and straight forward variable voltage regulator chips, which have built in overload protection are the best all rounder.

Commercial designs try to deal with as many variables as possible, so building your own can fine tune to what you have much better. It is also very inexpensive,... £10 would build a comprehensive spec., controller, with the exception of the transformer for power, the most expensive item.

hope this helps,

Stephen.

I can't answer your question directly, but if you want to make OO flexible track look a little better with more realistic sleeper spacing, this chap has an affordable product to help you.

 

http://www.phd-design.co.uk/

Superb for track, but don't forget that RTR points are difficult to alter, a friend had started re-spacing Peco and then realised he would have to alter the points or build more scale ones like C&L etc.

Not Madness , but an oddity, a strange mating of a Mallet, shown as 082,.......and a BR standard six wheel tender, the seller is absolutely up front about it, but........!! ..I do like the "fits quite well"

http://cgi.ebay.co.u...e=STRK:MEWAX:IT

Stephen.

It also features the unusual "represengtati ve motion" which you don't hear so much about, these days

" 'ou mean it don't go a'rond"?.......look at the track , the fall away is built in....they taper evenly......

Come on,the weathering alone must be worth the £3.99...the Lima a low value as usual....

The other postings cover this , but may I add that many models are wrong on this point, it is rarely portrayed correctly on models, it is a complex area as not only "mass" is balanced, but also potential power thrust is taken into account, which was a matter dealt with by the CME's experience, often not scientific design.

I'd be far more concerned the designer of the loco left moulding lines on the cranks, quite unnecessary, especially on a high priced model loco.

Stephen.

I had a relco on my first layout when i was a kid. I was mostly old Hornby stell track and was a constant battle to clean hence being draw into the Relco idea. It never really did anything and i got rather sick of the electric shocks i used to get when touching the track.

One thing i did notice was that if i left the layout powered up by accident my dad would go mental because the relco would put out that much HF interferance that he couldn't get Radio 4 in the kitchen! It seems the track was acting as an antenna and the relco a short range HF transmitter!

More notes for poster and other users.....use advice as relevant....

I am afraid the results you got were typical, as Relco did not supply the clearest of instructions, and modified the unit to two ways of operating, one being in series with the whole lot, which gave the interference, and powering with a separate feed with suppressing capacitors and RF chokes, which was the later way now adopted by other makers. The capacitors and the correct fitting, preferably with RF chokes as well are vital, and all locos have to have fully working suppressors and RF chokes as well.

Most users are not electrical Engineers, and Tri-ang and other makers barely helped in the old days with decent suppressors.

Steel track never worked well with Relco, the chance of a bad contact was more, and the unit fires up all the time. The voltage being felt is in the hands of the Gods, some people are very sensitive to any voltage.

The shocks were an indicator the track and loco pick-ups were bad, and the unit was working overtime!! As can only be repeated, first clean everything, and then the Relco keeps it going,(as does DCC on it's own in similar way)

People forget the wheel pick-ups being out of contact also made the unit fire up, any loss of contact did, so and an old Tri-ang loco with steel wheels on steel track with slack pick-ups was a very poor recipe for success, the Relco unit must have been running all the time.

Quite how an "out of action, but power connected on" track would trip the Relco into continous operation is very difficult to understand, it's impossible in theory, as the Relco shuts off when there is no load, but attempts to apply a high voltage, but it has nowhere to go, unless the track was in some way so corroded that partial current could flow and kept tripping the unit. The proper capacitors and choke in the power feed cures this sort of situation occurring.

This condition will not occur on any normal modern track like Peco. Oddly fine scale track with pc sleepers can have trouble, the gaps can conduct if dirt builds up. Make absolutely sure the capacitors are fitted and RF chokes as well.

Stephen

The original boxes for the Acro Teeaness Bogies.

Any body get a catalogue surviving?

Stephen.

Reading all of the above especially this piece about the new unit

The Electrak works by generating a high voltage, high frequency signal that is current limited to about 2 mA.

Due to the current limit, almost anything that is attached to the rails (e.g. a motor in DC or a decoder in DCC) will act as a short circuit to the Electrak. Thus, loads on the rails normally short the generated signal. Current flows from the generator, out one wheel set, across the rail load, into the other wheel set, and back to the generator.

Due to the low impedances involved, there is very little voltage in this loop (hence its safety and compatibility with DC and DCC). When the Electrak encounters a spot in the track that does not provide a good connection to the Electrak wheels (i.e. a dirty spot), the full 216 volts of the generator appears across this high impedance.

This high voltage acts to break up the contamination, and thus clean the track.

 

Now as I read it, as soon as a bit of dirty track is found & the short circuit created by the load being a decoder disappears, the unit reacts & off goes a high voltage spike cleaning track - I am lost to understand this as surely if the dirty spot was 2" long & the loco was a large 6 axle diesel that picks up on all whels, the short will still be there so the unit could never fire! Am I wrong? What good is the unit then? Would Relco on DC be any better in this situation?

Inserted Edit I think you may be mixing up terms for a "short" , with a "break", which is what sets off Relco. I do see that you see the decoder and motor load as a "short", and this goes as the break occurs, I agree, quite right, the lack of flow is the set off point.

Covered before in the replies, if many contacts are made the unit will not work, but then the loco is running fine,so it is not needed at that point.

Most of the time it does nothing, it only fires when needed, when run right, all is all right!!

It does not clean 2 inch strip of dirt, it does not clean at all, it gets the current flowing only in the micro second the current vanishes, breaks the gap, and then microseconds later the normal operation returns.

It's normal operation is too "not be operating", just like a fire brigade, always there, but you hope never called upon, so to speak.

In practice it does fire up all the time, randomly and it does indicate this with the cleaner wheels evidence, although again it does not clean them off as such, it keeps clean wheels cleaner.

Stephen.

They do run well and were made in quite a variety of types. Are these Arco or Acro? There was also Nucro and Teaness who all seemed to be the same products. Maybe you know more and can give more details as would be interested to hear.

Yes Acro, and the makes were all the same, or connected. I'll go and get the boxes and the camera, fortunately they came boxed in original tissue etc. They were sometimes looked on as simple construction, but the joy was the one piece construction, true and accurate.

The failing was the brass spring sometimes not matching the outer frames, axles did not always line up, I guess from the range the factory picked out the wrong base to assemble sometimes, as I can't believe they went to all the trouble of a casting without matching the spring bearing plate.

The heavy Exley's and Hamblings coaches run very well on these, but they need the extras added like tie bars, cross brake bars, and brake shoes. Sayer Chaplin die cast coach shoes, later done by Hamblings appear designed to fit (or the other way round).

Some older UK made Model railway items, some sets of LMS and GWR bogies from Arco, made in the 1950's and early 1960's. (From Ebay).

One piece die cast bogies, no brake shoes or tie rods, they had to be added by user, but fully sprung, with internal bearings.

They are superb runners, the wheels have a fine profile, and run absolutely true, and the other pair fitted to an Exley body run though the test track to perfection. They need a strip, added brake shoes, Sayer Chaplin cast coach brake shoes, and tie bars fitted, and a proper re-spray with an undercoat, which they do not have at the moment.

Surprisingly free running, no pin points here, plain internal bearings, but they are very smooth. Destined for some Exley GWR and LMS coaches under restoration at the moment.

Stephen.

A quickly grabbed shot at speed of the secret Eurostar testing the new French Duvet to keep it warm in France before the tunnel......

Stephen,

 

You may find some useful information here; http://homepage.ntlw...manus/plans.htm where a free plan for the M/V Vital Spark can be found for download.

 

Cheers,

 

David

Yes, I have the plan already, it is of an early open top type, not quite the type actually mentioned by Neil Munro, who placed Skipper Para Handy in a wheel house in several incidents in the stories, but as the Vital Spark would have been old in 1920 it could have been a conversion from an early open tiller type, always in those cases one of the Crinan canal lock restriction type.

many thanks,

Stephen

Stephen - I have 17 photos taken 2 Sept 2000, of a puffer, VIC 32, in Caley Marina, Inverness. They are mainly details of things like the winch, and were taken with a very basic digital camera, 640 x480, but if they might be of use, send me an email address This is one that has been brightened slightly in PSP

Jack

Many thanks for the kind offer, I have to admit that I do know a bit about Puffers, having built several now, and having a scratch built R/c one that was an entry for the Model Engineering Exhibition and the Sandown, and Brighton model shows. I'll PM the email to you as any extra shots are worthwhile, although I have never modelled one of the War Dept VIC types.

Photos of the early "real" puffers are quite rare, I have the books etc, and some privately sourced stuff, and a DVD copy of "The Maggie"!! I have also sat through modellers talking about "The Vital Spark" and how accurate a model is, biting my tongue, before reminding them gently that it is all fictional from the pen of Neil Munro, writing as Hugh Foulis!. The current "Vital Spark" is a Vic dressed up as an earlier type.

With Puffers it's all the extra bits and pieces that make the model, this new one is not quite right on a lot of points, but with additions and cover ups more than passes muster.

I am trying to source a good material for the tarpaulins! They are needed as the wooden covers are a bit simplified, with no way to secure or remove the planks, and no taper blocks for holding the tarp covers in place. The old model used old Victorian red and green dyed satin cotton handkerchiefs, with a doped finish!

Stephen.

looks really nice, and for the price the hull shape isnt that bad at all. I would be very tempted to ditch the very dodgy looking ship's boat for something more scale- I have used this super little range before http://www.model-doc...1_48_Scale.html

It would cost more than the whole Clyde Puffer!!..... I might be tempted to make one, but it's to the same standard as the rest of the Puffer and will get a tarpaulin fitted to partially cover the plywood sheet look.

The Puffer bow shape annoys me a bit, they got the shape of the hull correct except for the bow which should be vertical on typical puffer hulls.

Stephen.

Relco operation depends not on an ultra high voltage, in fact about 40 VAC is the lowest that track cleaning circuits will work with, but Relco does generate higher spikes. My own designed circuits are limited to about 100 VAC, I do not know the upper limit for a Relco, offhand, but I seem to remember testing on a scope with spikes of about 200 VAC peak at very, very low ampage.

The air is ionised in the gap, just like in a spark plug in a car, and voltage applied causes a small current to flow, which being AC breaks the insulation properties of the air further and reconnects the current flow. The unit does nothing if the contact is OK, and stops as soon as contact is restored, in milli or micro seconds.

The new US HF "cleaning" units work with voltage limitation, and fast clamping of the signal, and do not interfere with the Digital signal to the chip, and should not cause any breakdown in the chip or the board.

Note very carefully the bad use of the word cleaning, as I mentioned before the last thing these units do is clean the track!!! They just maintain a circuit, that's all, they do not remove, destroy, vaporise, or teleport the dirt away!!!!

The track and wheels must be clean to start with, and the Relco and equivalents maintain contact if the dirt gets in the way, that's all.

Stephen.

Shot of the more re-built 1:43^rd O scale Clyde Puffer Vital Spark, with extra detailing and rigging, reduced vents, and re-built bridge, with wheel and interior, now painted in more correct colours. Pulleys etc have been added, as well as davit and winch for the anchor lifting. The head looks better now, less like an Aussie dunny!

Lettering still to be sourced and final details like the funnel braces to go back on.

I am not using it on the Hastings layout, but will be using it on a small O gauge layout later this year.

Stephen

Shows layout for main drive, wire in the track groove, with cord to pulleys, one powered by geared motor, scale and size arrangement to suit your layout.

With the gearhead motors the drive for rotation is very straightforward, simply replace the main bearing with the motor, and the jib drive is as simple as a pulley drum on the motor shaft in the cabin, mounted again direct on the geared motor shaft, nothing complex at all.

Pick motor gearboxes with at least 200:1 or more, even over 1000:1 if available. Some surplus DC motors may be found at shows with these gearboxes fitted. Any DCC decoder could handle the control, or use mechanical switching.

Stephen.

I did one of these many years ago, in the 1970's for a display at the London MRC Easter Exhibition.

The drive for the whole thing moving involved using a straight quayside track, with one side of the track, (they were double rail like a tram track), having a hidden piano wire laying in the track groove, with the wire end bent up to engage the whole crane.

The wire was led along the track groove to one end and was connected via cord to a pulley, (several turns to get grip), and a hanging weight, with the pulley controlled by a slow motion DC gear-head motor. The other end was taken to another pulley at the other end, with a weight to tension the return motion. (The weights were 1 lb bag of sand!). It moved very slowly, at about a foot a minute at minimum.

The rotation was done by another gear-head motor, and a further one added for the jib. the control was by 2 rail pick-up from the track, with a RC tone decoder, so the best modern equivalent would be DCC , with two decoders, and a DC drive to the main movement (or another DCC decoder). The track can be basically two rail, you will need metal wheels etc and pickups. The whole crane will need a lot of ballast weight, and a bit of strengthening all round.

The weight return system was chosen to eliminate needing tension springs, which a continuous loop of cord drive would need. I found the cord slipped to much with spring and induced drag, which the weights eliminated.

Supplier of the motors, (with the highest ratios gearboxes) try: Precision drives , no connection except customer.

Gears can be scrap, or inexpensive plastic gears for modellers, several sources.

Stephen.

As I was browsing Ebay, I spotted this very nice Clyde Puffer ship model, a wooden Far eastern model, in O scale size, at ??9.95!!!

About 16 inch long, quite detailed, well finished, but worth a spot of re-working and detailing up. the hull has the right lines, albeit a bit shallower in draught than most real hulls. The bridge roof was far too large and needed cutting down, and the windows are a bit small as well, but left for the moment.

The rudder is now on the right way up!, and the fluffy cotton cord replaced with woven black silk. Most of the brass eyelets are replaced with small cast ones, and some cast details added like a door for the engineer to get into the engine house!... coalholes, ladders, steering gear cover plates etc.

A few items have been moved to the correct positions, and further work is planned like block and pulleys and proper rigging. The rear handrails could also be worth replacing with a scale brass one with two rails, the current one is single wire in split pins, neat but too low.

The rowing boat has been stripped of paint, and will be stained and varnished. Very nicely detailed with paddles etc inside.

The crew with be sourced, and some lettering for The Vital Spark, Port of Glasgow, as the model Puffer is pretty near the type that Hugh Foulis wrote about in the famous Para Handy Stories.

Nothing has been re-painted as yet except the roof of the bridge, which was sanded to size and filled, then stained black. The unpainted white metal parts are visible in the shots, bases for the vents, buckets, eyelets, and lots of detail castings.

So a quayside 7mm shunting layout will be needed?!!!!

Stephen

Stephen, with all due respect, but those 'one-of-a-kind' tests are IMO not representative for the purpose you've intended to show. DCC tracks are much cleaner in the first place, as decoders suppress the BEMF spikes, and safer cleaning can be obtained by using a cleaner car. That way you can be sure your decoders will not suffer from any damage a RELCO style unit may or may not bring.

Maybe to not confuse the average user, perhaps I have over simplified too much in the replies, but........

Hardly one of a kind as I sold units based on these circuits some 35 years or more ago, and the design was very, very, closely looked into, I am a qualified electrical engineer, and proper research and design was always done.

BEMF suppression does not affect the HF signal, different frequencies, and back EMF does not clean, or dirty, or influence the track tarnish in anyway, it's too low a level to break tarnish, which starts at about 25/30 volts.

Our model motors do not generate such large signals, the BEMF suppression is to ease the reading of the digital signals, and help prevent spurious pulses being interpreted by a DCC decoder.

Please note, track tarnish, this is all Relco or equivalent, will remove, NOT DIRT, OIL, OR MESS OF ANY TYPE.

This is the most deeply miss-understood aspect of these cleaners, they do not clean track!!!!!!!!!! They keep cleaned wheels cleaner, with a satin matt finish usually, that stays clean with no tarnish or oxide build up.

If all you run is nickelchromed wheeled Chinese models, then Relco would not have much to do, chrome does not tarnish in the same way. but most modellers have a mixture of makes and wheel finshes and most respond to the HF cleaning, as does most nickel silver track.

Steel track is different, the HF signal appears to induce some corrosion as the device is used, due to the iron oxide flaking more on removal, and steel track can become a bit rough in use with these devices in the very long term.

I did say very clearly the separate cleaning car offered would be safer, but this does not imply the direct use is unsafe, it is all relative.

When a DC model train proceeds down the track, although it seems to proceed smoothly, without lose of contact, or any visible effect, try putting a scope on the circuit and see what is happening, it is a constantly dynamic situation, with the current going up and down rhythmically with the motor rotation, and minute, and constant spikes and jumps and jitters in current occurring, plus BEMF effects, sending the voltage up and down from the applied voltage.

Even in this "perfect" situation the Relco does actually fire up, a few cycles, occasionally, an effect that can only be observed with a digital tracking scope, and is completely invisible to the naked eye, so to speak..micro breaks occur all the time and may last long enough to trigger the Relco.

I have also checked the exact situation on DCC, both a new home made unit and an NMRA approved design, and the digital signal is so much larger, than these effects, it does seem to suppress the Relco firing up, but it is there intermittently if you look hard enough.

It comes on during the spaces in the DCC signal, if there is a poor contact at that point, it is operatng at the signal speed, a dynamic situation, again observable only on a digital scope, I have an older PC devoted to digital grab display, and recording voltage and current tracking. the trace shows no operation at zero cross point of the signal, obviously no current is flowing then, but the HF comes in during the rise and especially the fall of the digital pulses, but again only if the signal fails to get through, all of this is happening so fast it is unobservable except on digital grab.

A lot of the time Relco does nothing, due to the good contact, but every so often it does operate, and as practical observation of the wheels show it is keeping the wheels cleaner than without.

None of this is a comment on others comments, just notes to outline the use and help outline the operation and possible pitfalls of these devices.

My personal position is that DCC has a poor record on the issue of track cleaning and running quality, if the signal had been raised to 40 volts, and the pulses applied, the cleaning action would be automatic, and tarnish would be broken naturally, but the German designers at Lenz, when they took the early Zero One design and other development work, adopted the lower voltages, due to chip limitations, and the computer practices of using low voltage as far as possible, and we have to live with a simplified Digital Control System based on commercial priorities rather than electronic excellence.

The US designers in the 1960's, who pioneered the use of what was to become DCC, made the use of a high standing AC voltage a cornerstone of the idea, with track tarnish cleaning in mind, but it all got forgotten when the industry got around to being able to make the Digital ideas practical.

Hope the notes make it clearer, the waters are already muddied about Relco, let alone adding DCC to it!!!

Stephen.

I should add that practical examination of wheels showed that even when several trams ran at once there was still cleaning, and I made up a DC test train with lighting to see what actually happened with more conventional set-ups, and even with the load of the lamps on it, the Relco operated whenever the motor lost contact, as there is a sudden change of load which triggers the HF in most situations. This would be especially true with today's low ampage LED lights, they draw low current , the motor high and the contact loss to the motor triggers the signal, which would be damped by the lighting somewhat.

What happens with dozens of locos on a large DCC layout is pretty obvious, nothing at all!!

So triggering may well occur in practice on DCC even with several locos, I do not know how the US designers have allowed for this in the commercial unit.

The proof of the pudding is in the eating, and with multiple DC tram set-ups cleaning still occurred, the usual proof was clean blackened brass wheels losing the blacking on the contact area. The Trams used Jackson brass wheels, and without the Relco wore to brass., but with Relco developed a matt sheen on the tyre, always clean.

The same applied to 00 wheels like brass Hamblings, whick were blacked, and wore in the same characteristic way that Relco induces, a matt sheen on the surface with extended running.

Stephen.

Presumably this unit would not work with stock that has resisted wheel sets present on the track, or on systems that had more than one loco on the track, the high voltage would never be generated as there will always be some form of continuity across the rails.

 

Relcos were always fitted one for each controller so were only ever (normally) trying to power one loco at a time, in DCC this situation is very rare as all locos share the same power source.

 

Andi

This was always a little understood bit of the operation of Relco, if the loco was in contact and other items were in parallel, say lit coaches, then the device will not fire up, and with a DCC system with more than one running at a time the same must occur.

My own set-up rarely runs two at once, so the unit does work, but a big layout will damp the operation, and in theory the unit never functions at all.

If it all is working, then Relco simply sits there doing absolutely nothing at all, all the time, simple as that!!!!

But the logic of this seems at first glance very perverse, if it does nothing then why have it? but it's the point of the device to make things run, and if running, then the track is OK, and the device is out of action. The same applies to DCC, if it is running, then all is well.

The only way to guarantee with DCC some cleaning action, would be to run one loco and nothing else for a cleaning session on a large layout, or use the towed cleaner B unit.

This is why the makers in the US offer the vehicle based unit, a better idea with DCC and DC all round, but it is US outline and big, too big for an 00 layout.

As I said before,on a big well used layout tarnish is not a problem, just awipe over will keep clean, but on small end to end, or small scale like N , it can pay to use the devices. I would never bother on O gauge, the weight guarantees contact.

My own reason for researching these and using them is for trams with overhead contact and it works very well here, as it does with any overhead system on DC. it would work with DCC, but with multiple feds may well be masked of and never come to life. My own choice with DCC and over head, would be a feed to the over head being isolated from the track power anyway, perhaps even using DC feed to the track for coach lighting, with a shared return for the separate signals.

And by the way, the HF devices do not add spikes of hundreds of volts, about 25vac to 30vac HF is applied during the operation of a single cycle, that's the RMS value approx., of the spike, it can exceed that voltage for a while on each cycle, but it will be a low average. It is not a zap of high voltage!

Stephen.

Well... whilst I was designing the modifications to both the Relco and a home made version of HF cleaners, I contacted a leading supplier in Germany, who I cannot name, and they confirmed that the system is safe with suitable precautions.

However as usual with the continental makers, they refer to the original idea of DCC have a sufficient standing voltage to over come dirt on the track, and extra cleaning would be not needed. The arguement is that the mark space digital signals will get through to the loco, and give control, but the current required to propel the loco has to arrive at the loco, and the tarnish etc., may reduce the power available, and the HF unit may help maintain contact.

They do chips that overcome this in a different way, but confirmed that the DCC signal is not affected by the HF one, as long as strictly current limited, and of short duration.

The silicon chips do not deteriorate or age with high voltages, the main trouble possible with a HF unit is the use of modern lead free high tin solder, which can cause a condition known as "whiskers", minute crystals of metal that could short tracks out on PC boards of the decoders.

The HF cleaner signal could jump the gaps more easily, but the input stage of the chips are designed to damp such voltages, and the chips are protected with Zener inputs, there to stop static and handling voltages.

I was also told that makers had made tests with the chips in the States and all worked with the HF systems very well. They were testing it to see what would happen. I believe that the NMRA have an application for conformance for these US commercial devices and are looking in to it.

As I said before I cannot really publish the circuits, they might or might not work with all chips and I cannot be responsible for mass destruction of the UK MR communities chips!! However the US supplier is able to offer the same option commercially, and I can see the way the unit operates.

There are still those around who refuse to believe the Relco worked at all, and do not understand the operational details for DC use , let alone DCC. I have heard everything from destruction of a complete model to one bursting into flames due to the devices, frankly impossible. I have heard descriptions of the action as using ultra high static voltage to Zap the dirt at over 2000 vac......and one man blamed the demise of his Hi-Fi on one of them.

All I can say is that they work, as does the equivalent circuits, understandable operation, and yes, DCC will work with reservations, but if you want peace of mind do not use them...... Horses for courses......

Stephen.