Cobalt Motors and DCC how do you control yours?

[Wogga]

The conclusion of my two years faffing around with Cobalts and Switch 8's can only be the current drawn by the Cobalt exceeds the potential of the Switch 8's. Secondly there are no bad reports with Tortoii and Switch 8's anywhere.

 

I fitted an AD4 and my problems on that section of the layout seem to have gone. I am a bit peeved to say the least that I need to go to more expense when all I was doing was following manufacturers instructions, neither NCE or RJ have been transparent.

 

NCE Switch 8's with Cobalts? Good luck you will need it! I cannot and do not recommend this combination.

[Richard Johnson]

*** If I had noted this thread earlier I'd have commented earlier, but its been a busy few weeks. Re that last comment - and after so many minor issues with Switch 8, and after long consideration, nor do we really any more.... but its nothing to do with current draw as the Switch 8 should be able to deliver 50mA which is 2.5 times whats needed for Cobalt. With zero regulation and headroom in its circuit, Switch 8 rapidly lowers output voltage with any load above 10~15mA so its to do with inadequate voltage delivery via Switch 8, thats all. We will soon revise our instructions totally and make this clear.

 

Its pleasing to note that using our AD4 or with decoders of many other brands, there are no issues. (a couple of brands do need a pull-up resistor added, but they acknowledge that in their own customer support).

 

I do not agree that we are not transparent - we are far more open than most brands (who else gives direct forum comment) and have always been both supportive and helpful where any problem has surfaced... and we back and help our users very strongly without fail, whether the root cause is our fault or not.... and "Not working but not our fault" by far leads the causes of frustration. (despite that, as with decoder damage caused by loco makers careless assembly of sockets, we still look after customers at our cost because nobody else would).

 

The result is, most who have problems, irrespective of cause, will get help and usually a positive resolution via direct contact quite quickly.

 

Since release of Cobalt we have already made several small changes to try to compensate for problems created by wrong usage and voltages... an intensely frustrating process in that its been "lack of care" and wrong combination issues that we have not considered (we can't test for every possible combination) that have been at the route of most discussions we have had. Most are easily fixed, providing that our advice is acted on. Most of them, providing instructions are actually read, are not so much users error but mis-information, lack of attention to instructions and misunderstanding, and others are simply combinations that we did not expect.

 

Overall, while forum threads always contain those few with issues, an occasional fact and a lot of is-information and guessing, the reality in the marketplace is most customers with zero problems, and a few with many, because its their specific combination of circumstances that is at the root of most things.

 

Having scanned this thread, I'll go through some of them.

 

Voltage: This is the core of most things.

 

We clearly recommend 9 to 12v as ideal. Sometimes modellers think that is what they are applying but it isn't and either over or under voltage results. Many do not even read instructions in the first place. If we do not increase internal resistance to increase tolerance for over voltage, damage can be caused. If we DO increase internal resistance to allow for over voltage, then Cobalt can not drive at low voltages. Neither issue is actually Cobalts fault, but Cobalt is the point at which the symptom displays so it gets the blame. We continue to look at this actively.

 

Example - trainset controllers marked 12v DC uncontrolled - these are usually 15~17v DC at low load, not 12v, which they only approach at full current limit. Result - overdriving and damage.

Example - low track voltage when using a decoder with, for example, Switch-8. Switch 8 has NO driver power and NO voltage regulation onboard at all having been made to be low cost. It simply relies on the IC outputs directly. If power exceeds a few mA then it lowers voltage. If input voltage is already low then Switch 8 output is even lower, meaning that there may be not enough power to drive Cobalt.

Example - Power Supplies (wall plugs or any in fact) that, like trainset transformers are not regulated - up to 19v has been measured on our tests for these when mains line voltages are high... yet these same units were labelled "12v DC uncontrolled"

Example: Home made power supplies where the owner doesn't realise that rectification and filtering increases output voltage on DC well above the transformers AC rating (it does, about 1.4 times in fact)

Example - using Lenz LS150 or any AC output solenoid decoder with a singe diode. This gives half wave power which = half voltage, LESS the diode drop, which, unless the actualy voltage input is above 15v for the accessory decoder can be too low.

Example - DCC systems with excessive track voltage - many from EU are like this.

Example - DCC systems with low track voltage - for example where voltage delivery is low because of wiring quality OR because power supply choice is wrong. Some UK retailers sell ex US units with mains supplies that are below the needed voltage.

 

So - we have learned a lot - mostly that specifying an acceptable voltage range isn't enough... we have also changed internal regulation slightly but some users still manage to over-drive things despite our best efforts. Even so, overall reliability is still very high and more than 90% of units we have had back DO work well when driven within specification... We are working on this constantly, and we will see what comes out of it in future... We never stop working to try and make things as good as they can be.

 

The Case. I note a comment about the case earlier. The internal relationships of the case are 100% perfect - Yes, there is a slight angle on the outside of each half which is to allow easier tool ejection when moulding, as an easy eject is importnat to engineering plastic as it leaves the tool quit soft... but this has absolutely NO effect on internal gearing or parts relationships or final installation on the layout - the internals of the case are very well designed mechanically and there is NO possible relative movement, full stop.

 

The ONLY problems we have ever had related to the case were assembly based. All were fixed immediately they were found. One was related to improper tightening of screws and the other to not allowing the cases to settle properly after rmanufacture. If the cases are assembled too soon after manufacture, then being an engineering plastic not a low cost material, they have not had time to settle and stabilise which they do need. This resulted in very slight shrinkage after assembly resulting the two bearing halves over-gripping the gear shafts and if voltage was also low, it could cause a stall. As this is not discoverable at time of manufacture (shrinkage takes some time to settle) some did go out into the market before we found the issue - however to fix this, as soon as we discovered it, we introduced a quarantine in manufacture before case use, solving it totally.

 

FYI each batch is 100% tested on-line followed by both random tests and a "life test" which usually exceeds 120,000 cycles, is occasionally 140,000 and never fails to exceed 100,000 cycles using the Cobalts own internal switching to count therefore testing both mechanism and switch. That exceeds the highest "Mil spec" so we are comfortable with general quality - however because users are users, we continue to evolve things incrementally and will probably make minor changes as time goes on and we can still find new benefits or solutions.

 

With a very high 5 figure qy entering the market each year, I guess there will always be the odd problem here and there, but I can guarantee that anyone who contacts us will find both support and a resolution that is more than fair.

 

Richard

DCCconcepts

[two tone green]

Hi Richard, good to hear from you.

 

Could you give a possible cause for considerable difference in the noise given off by the point motors. My original twelve purchased soon after their release are quiet in operation and the six along with six replacements for them bought in the past month are very noisy in comparison.

 

Even before mounting on the layout boards the noise from the new ones is very noticeable. Has there been a specification change in the materials used for the gear components to cause such a difference.

[Ravenser]

Some comments from a slightly different perspective - a different kind of set-up

 

For Blacklade I bought a batch of Tortoises . I then found that because the station throat is across a very narrow "neck" on the boards I couldn't get all the Tortoises into the very constricted space , so I ended up buying a Cobalt and a Hoffman

 

The installation is illustrated and described here:

 

http://www.rmweb.co.uk/community/index.php?/blog/343/entry-6834-points-arising/

 

but the key point is that based on previous advice and experience with a group project , points are powered through a completely independent supply, and only the data signal is taken from the traction buses

 

Power input to the DS64 used on this board is 12V DC from a  1 amp regulated supply fed by the 16V AC auxilary buses (I can't remember whether this is Express Models or All Components: as I'm away from home I can't check - though this board got the 1 amp unit to feed DS64, portacabin lights and signal LEDs - the other board got the 0.5A supply , for signals only)  . I understood from postings on this forum that if 16V AC was supplied to the DS64 power input it would destroy the decoder , despite Digitrax' claim that this was an available option

 

The 4 point motors on the other board are Tortoises controlled through a MERG decoder , again with independant 16V AC supply , and 12V dc output to Tortoises 

 

I've had no trouble with the Cobalt , though the Tortoises and Hoffmann give some troubles . In the case of the Tortoises  the problem is the very stiff Marcway points, meaning that sometimes flexing of the throw arm is a path of lesser resistance than fully throwing the point. The Hoffmann buzzes in one direction on occasion (indicating failure to reach end of travel and cut off) and may need its alighnment adjusted

 

Out

[Gordon H]

With zero regulation and headroom in its circuit, Switch 8 rapidly lowers output voltage with any load above 10~15mA so its to do with inadequate voltage delivery via Switch 8, thats all.

 

To reinforce what Richard says, have a look below at the current sink and source specifications for the LM324 (which is apparently what the Switch-8 uses):

 

 

In particular, note on the source graph (Fig 14) how drastically the output voltage falls (shown here as a rise due to the way it is measured) when the current drawn rises above about 10mA. The LM324 is clearly not a particlarly good choice for this application.

[melmerby]

 

To reinforce what Richard says, have a look below at the current sink and source specifications for the LM324 (which is apparently what the Switch-8 uses):

 

LM324 Current.png

 

In particular, note on the source graph (Fig 14) how drastically the output voltage falls (shown here as a rise due to the way it is measured) when the current drawn rises above about 10mA. The LM324 is clearly not a particlarly good choice for this application.

Perfect for the application it was designed for. (and it works perfectly with two Tortoises -approx 24mA)

Quite clearly IMHO the designers of the Cobalt picked the wrong motor specification not checking the Switch 8 specification properly, before claiming a Switch 8 would drive a Cobalt (have I read that correctly?).

 

Keith

EDIT:

I'm starting to get a feeling that the Switch 8 is being rubbished because it won't drive a Cobalt, which is a little unfair, as AFAIK NCE never said it would drive a Cobalt.

How much current at what voltage should a Cobalt be using?

[Wogga]

Thanks for all the comments it has been very constructive, based on economy and the effort involved I have decided to go down the AD4 route. I will hopefully I will get some return on my Switch 8's.

 

All I need is to find a cheap source of AD4's cos I need four, the pricing in the Uk is neigh on 25. - 30% greater than what RJ sells them for. Plus there are not as many suppliers as there used to be I'm finding?

 

Is there any benefit ordering them direct from DCC Concepts?

 

It has been a frustrating two years + but now it is clear there is a compatibility issue but as far as I am concerned it is onwards and upwards.

 

Thanks again all for your feedback.

[Gordon H]

Perfect for the application it was designed for. (and it works perfectly with two Tortoises -approx 24mA)

The LM324 is not intended for motor driving of any sort. It is a simple (quad) small signal op-amp whose output only swings to within about 3V of the positive rail.

The fact that it manages to move a Tortoise does not mean that it is a good choice, as it is clearly near the edge of its capabilities.

Simple derating principles ought to have eliminated it from selection for this application.

Not sure how the manufacturers can claim operation at up to 50mA, given that the datasheet clearly shows the in-built current limiting only manages that level at -55C. Clearly it is being used beyond the recommendations of the datasheet, which is bad news as a matter of principle no matter whose device is being driven.

[melmerby]

The LM324 is not intended for motor driving of any sort.

 

Where does it say that in the LM324 specification?

The ST datasheet: http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00000457.pdf

 

NCE claim a Switch-8 output will drive one Tortoise (approx 12mA) and say it may drive two but it is not guaranteed.

It also says trying to draw more than 40mA will invalidate the guarantee.

 

Each output of a Switch 8 is driven by two LM324 sections, one goes positive, whilst one goes negative and vice-versa.

 

Keith

[Gordon H]

Where does it say that in the LM324 specification?

The ST datasheet: http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00000457.pdf

 

NCE claim a Switch-8 output will drive one Tortoise (approx 12mA) and say it may drive two but it is not guaranteed.

It also says trying to draw more than 40mA will invalidate the guarantee.

 

Each output of a Switch 8 is driven by two LM324 sections, one goes positive, whilst one goes negative and vice-versa.

 

Keith

 

It doesn't need to say it explicitly. It is clear from the spec that it is intended as a small signal amplifier, whose main claim to fame over the 741 and similar is the ability to work down to the negative rail, and therefore is suitable for single rail operation.

Anything intending to be used for motor driving would be classed, and known as, a power op-amp.

Are there any application notes showing the LM324 as a motor driver? I've never seen any.

The fact that two sections are used per motor merely indicates that they both share the same current so both sets of losses apply (the graphs I showed previously). The 40mA figure is based on the in-built current limit feature which shows 40mA on the Fig. 4 graph for 25C, i.e. approx. room temperature.

This is a case where the circuit is right on the limit of being able to do the intended job, with little or no spare capacity for coping with variations of power supply voltage or motor current.

Perhaps they should withdraw the part of the statement suggesting that it might drive two of them. If they can't guarantee it, why even suggest it? This is bound to lead to disappointment when it fails to do so.

[melmerby]

Why do you need a power op-amp when very little power is required?

A Tortoise draws no more power than a LED and the LM324 is used for driving LEDs.

 

 

For comparison I obtained some figures by testing the various options today:

 

DCC into Switch-8 = 15v AC +/- 0.1v (On true RMS voltmeter)

Switch-8 output no load = 13.5v DC

Switch-8 output one Tortoise connected stalled = 11.7v, running 13.0v

Switch-8 output two Tortoises connected stalled = 7.5v, running 12v

Switch-8 output one Cobalt connected stalled = 8.8v, running 11.5v

 

With a regulated 9v connected to a new Tortoise it consumed just under 13mA when stalled, 3-5mA when running (difficult to measure accurately due to variations).

 

static resistance of motor.

Tortoise = 660 ohms

Cobalt = 360 ohms

 

From the above figures it would appear that a Switch-8 should drive one Cobalt (8.8v stalled), virtually bang on what has been said a Cobalt should be connected to.

The 11.5 when running should be of no consequence as it is for a few seconds at a time and much less current is flowing.

Notable is the fact that one Cobalt running appears to consume more current than two Tortoises!

 

Keith

[Gordon H]

Why do you need a power op-amp when very little power is required?

A Tortoise draws no more power than a LED and the LM324 is used for driving LEDs.

 

 

For comparison I obtained some figures by testing the various options today:

 

DCC into Switch-8 = 15v AC +/- 0.1v (On true RMS voltmeter)

Switch-8 output no load = 13.5v DC

Switch-8 output one Tortoise connected stalled = 11.7v, running 13.0v

Switch-8 output two Tortoises connected stalled = 7.5v, running 12v

Switch-8 output one Cobalt connected stalled = 8.8v, running 11.5v

 

With a regulated 9v connected to a new Tortoise it consumed just under 13mA when stalled, 3-5mA when running (difficult to measure accurately due to variations).

 

static resistance of motor.

Tortoise = 660 ohms

Cobalt = 360 ohms

 

From the above figures it would appear that a Switch-8 should drive one Cobalt (8.8v stalled), virtually bang on what has been said a Cobalt should be connected to.

The 11.5 when running should be of no consequence as it is for a few seconds at a time and much less current is flowing.

Notable is the fact that one Cobalt running appears to consume more current than two Tortoises!

 

Keith

[Richard Johnson]

*** The implication that we should have designed Cobalt to match a "lowest possible cost" accessory decoder is almost funny. It was anyway actually released after the basic design of Cobalt was created.

 

BTW the system of drive is totally different between tortoise and Cobalt, and the shortcomings of Tortoise,, such as its huge size, significantly lower switching power, significantly lower power switch power handling and things like its tendency to relax and allow point blades to move away from the stock rail when powered down overnight are conveniently ignored.  also keep six Tortii on my retail demo layout to remind me how noisy they are (Given  the same drive voltage, they are certainly noisier than the noisiest Cobalts we have heard). 

 

Cobalt will draw 18mA at our preferred 9v. Slightly higher at higher voltages.

 

Switch-8 ***CAN*** be reliable with Cobalt however it does need a track voltage of around 15v to do so because of the steep voltage drop it experiences because it is, basically, an under-designed product. (Note too please - NCE's own Switch-it on the other hand uses a different output and works just fine). The same can be said about using half- wave power and a solenoid decoder (which always raises my eyebrow as its a total mis-match) ie: with something like a Lenz LS150... it can work, but only if the initial input voltage is a little above the specified 15v as half wave plus voltage drop via diode and less than perfect modeller wiring can leave precious little drive voltage...

 

BTW - taking on board the above comment - Switch 8 is not being rubbished at all - (but isn't it fair to say you were rubbishing Cobalt because Switch 8 uses a marginal power component that NO sensible designer would select??) .

 

It is simply agreed that it is NOT the perfect choice unless you are aware of the needs that the combination creates, and retailers who do not take the trouble to actually understand what they sell are the culprits, nobody else. This is a wrong choice/wrong application by the user or a recommendation that should have been accompanied with some advice based on real product knowledge by the retailer, not a problem for or because of Cobalt.

 

(However I agree that we did contribute to a degree because in our own tests it was fine as we tested using systems at NMRA recommended voltages, but our manuals WILL be changed to highight the issue in their next iteration)

 

Most importantly, the decoders that ARE designed to drive cobalt DO work reliably - and also give the option of button control which to us is an important feature. 

 

That in reality is all that we as the creator should be worrying about.

 

We are far more interested in making incremental benefit improvements in our own product ranges than worrying about what others are doing. Their problems are not ours.... and because we are focussed more on our own needs, you can expect to see several interesting products related to this subject during 2013 (already the high power version of our AD1 is available.... with 400mA available for multiple simultaneous motor drive control and of course for the far less efficient motor drives that are out there) BTW a side benefit of the AD-HP is that it turns off power after 4 seconds, leaving zero power bus usage between changes.

 

Other specific comments:

 

Two Tone Green: Re noise increase - no significant spec change but one batch trialled a new way of motor mount... I too found that it was inconsistent sound level wise so it was changed again. If you'd like to drop me a line at sales@dccconcepts .com I will send you a pack of foam mount pads no charge by airmail.

 

Wogga: where are you? Anyone who uses an LMS roundel as an avatar is always going to do OK with me LOL. Please email me and ask....

 

Regards

 

Richard

[newbryford]

(, but our manuals WILL be changed to highight the issue in their next iteration)

 

 

 

Richard

 

Hi Richard,

Will the manuals be updated to include the DCC Ready Cobalt (with integral decoder)?

 

Cheers,

Mick

[two tone green]

Hi Richard,

 

Thanks for the offer of the foam mounts but the problem is that the noise levels on the six offending point motors were high before they were mounted on the board as I mentioned in my posting. So even worse once on the board. Foam pads would not have help with the grating noise coming from them.

 

I have your various accessory packs that has foam pads, drills, template, camouflage hole covers so have enough foam pads anyway. But thanks to my very helpful supplier he has already exchanged the motors for the more quite type. He went through a batch to find some quite ones.

 

As I said, the difference between the initial batch of twelve I had, even mounted directly to the board, and the new ones is incredible. I remember your sales patter saying about how good your motor was and listed the benefits of using them. Silent being one of them. Whilst silent is impossible to achieve they are very quiet and very good when running normally. But certainly the new batch of six would have had any new or returning customer seriously doubting the sales patter and asking for a refund. As I have some faith left in the product I opted for an exchange and fortunately my supplier came up with the goods.

 

The faulty ones from me along with others he has had returned recently are being returned to Gaugemasters who I believe are the importers here in the UK.

 

But thanks again for the offer and your continuing support.

[melmerby]

Richard

 

I must comment further on some of what you have written

You say the Tortoise is "Huge" which implies that the Cobalt is small. IMHO I would not class something which is 83% of the length, 87.5% of the major width and 80% of the minor width of the item which it is being compared particularly small! Smaller yes, but hardly small.

 

I have two Cobalts, purchased a year or so ago. Both are noisier than the thirty Tortoises I have installed.

None of my Thirty tortoises ever "relax" away from the end point when left overnight or even longer. (Measuring a new Tortoise "out of the box" it needed between 600 and 700 gms to move it, enough to bend the wire actuator 90 degrees.)

 

Is the, undesirable to you, limiting effect of the Switch-8 really so bad? The voltage drop at stall reduces the dissipation in the motor at end of the travel.

The Tortoise is a proven design with many satisfied customers, so it can't be doing much wrong.

 

Keith

[Richard Johnson]

** Cobalt is actually less than 50% of the volume of T - 46% in fact. That is a reasonable difference. 

 

The relaxing isn't an invention, it is a known issue that has been there for more than 30 years - it is the sole reason why most stall motor accessory decoders have a slight movement at the time of power on (and the instructions do say why its there - to restore T controlled blade position).  As our AD decoders are also sometimes used with T, we also added it.

 

If the voltage limiting effect of SW8 was intentional and only at the end of travel it might be a positive, but its not.... it is a factor that is in effect a direct symptom of an over-design level load on the chip and it happens immediately a slight load is applied. In reality makes no difference to the dissipation in the motor.

 

All of that is not really relevant to the question that started the thread - SW8 has used a device that exhibits a sharp voltage drop under load and so right now it is not the right answer for other than T at this point in time unless other factors are properly understood, ... while purpose designed decoders are.

 

Its probably up to us to promote this point more strongly, which we will.... because we know that no matter what we say or write, such questions will always exist so we will do it both by adding information on how to make SW8 more reliable with Cobalt and how to get the best results by using the better matched options that do exist already.

 

In the end the desire is simply to make sure that things work as they should for modellers, and that means informing and helping as needed.

 

Regards

 

Richard

[Wogga]

Final post from me on this subject, first of all thank you to all the posters your input has ended 2 years plus of frustration.

 

I have fitted one AD4 to the existing Cobalts and it has run faultlessly for over a week under Traincontroller Gold v8. Track voltage from the ECoS is back where it should be. The Cobalts purr away nicely so much so I have to look to see if they thrown, which they have every time. Two of the outputs are driving two Cobalts each at switchovers with no issues.

 

I am so satisfied I have ordered another 4 AD4's to complete the layout. I could of got a better deal direct from Oz but I was so giddy and impatient I ordered locally.

 

So if anyone is looking for some NCE Switch 8's at £25 a pop send me a PM or keep your eye out Ebay.

 

Thanks again for your input it is appreciated, now I can get on with some serious modelling and get my Traincontroller schedules finished.

 

Regards

 

Pete

[Gordon H]

Sorry about my previous reply (Jan 3rd) having no apparent content, just Melmerby's quote.

I am still having problems with posting since the recent changes to the site, whereby 'Reply quoting this post' simply doesn't work as advertised, and neither does a simple reply which reports as an empty post when sending. Hopefully this gets through...

The main point is that the LM324 spends the vast majority of its time sitting with a stalled motor connected to its outputs, which as has been shown leads to a drop in output voltage because it is heading towards an internal current limit situation. Such limiting capabilities are generally put there for device protection, not as a feature to be used in normal operation.

When designing a motor drive circuit you would not normally expect the output impedance of the driving device to come into the equation, other than under fault conditions.

Given the efforts that most people make to ensure a minimal voltage drop through their layout wiring, it seems somewhat absurd to produce a circuit which has exactly that result by design.

[newbryford]

*

 

In the end the desire is simply to make sure that things work as they should for modellers, and that means informing and helping as needed.

 

Sorry to be a pain, but have you got updated instructions for the DCC fitted Cobalts? A friend has bought a dozen from DC Kits and the only info is a sticker on the decoder. As I mentioned before, it looks like the terminal wiring diagram has a couple of terminals incorrectly marked for the auxiliary switch.

 

Edit: - now sorted thanks to Tom E - see below.

 

Cheers,

Mick

[TomE]

Hi Mick.

 

The manual for the Digital is available here: http://www.gaugemaster.com/instructions/dcc_concepts/cobalt_digital_manual.pdf

 

This thread has been a very interesting read, as I have 6 cobalts fitted to my layout. There is a 50/50 mix of Digital Cobalts and orginal Cobalts with the AD1 decoder and they are wired directly into the main DCC power bus, which is powered by an NCE Power Cab. I have one motor which clicks once, sometimes twice, at the end of its travel and if my understanding from this thread is correct, this is the result of the Power Cab feeding to much voltage to the Cobalt? This particular motor is one fitted with the AD1 decoder

 

The rest have all been fine, however I wonder if this problem is likley to manifest itself across the other motors installed?

 

Tom.

[newbryford]

Hi Mick.

 

The manual for the Digital is available here: http://www.gaugemaster.com/instructions/dcc_concepts/cobalt_digital_manual.pdf

 

Hi Tom - thanks for that - I couldn't find anything on the DCC Concepts website.

 

Cheers,

Mick

[silverlink]

This is all very interesting, our club layout has more than 30 cobalts fitted & I think seven switch-8's & we have had lots of failures with the switch-8's with certain numbers not wanting to work. I sent five back to the retailer who checked them over & sent them back with four having no fault found & one with a dry joint which he fixed. Refitted but again more faults with odd numbers not responding to handset (Lenz 100) could it be a voltage thing as mentioned?

On my exhibition layout 'Haymarket Cross' I am using 25 Tortoise motors worked from DPDT switches on a schematic panel  with all our operators preferring this type of operation to handset selection. I would say I can easily change five or six motors this way as apposed to one with DCC handset.

Haymarket Cross Control Panel

 

Ian H