jamespetts

I have uploaded a new video this evening about stay-alive capacitors, why they are needed, some alternatives to installing them in some cases, different types of capacitor, the need for charging circuits and more. Watch the video here: Particular thanks to Jennifer E. Kirk, who kindly gave me permission to use some of her archive footage in the video.

I got one of the new ones; here is a comparison between olive green DJ version versus the olive green EFE version: O2s by James Petts, on Flickr O2s by James Petts, on Flickr O2s by James Petts, on Flickr

One can also use JMRI for scale speed matching, I believe.

I approve of layout inspiration...

Westbury?

A basic principle to keep in mind: the wire should always be rated to be able to take the maximum current that the power supply can produce, subject to any fuses/breakers or similar protecting it. So, if your power supply can put out 5A, the wire needs to be rated for at least 5A (preferably more than 5A to give a margin of error), unless you have something like a District Cut-Out (e.g. the MERG DCO) in use, in which case, wire downstream of the DCO can be rated for whatever the DCO is set to (e.g. 3A or 1.5A). The reason for this is that, in a fault condition (e.g. a resistive short), it is entirely possible for something slightly less than the power supply's rated maximum to be drawn. If a current in excess of the wire's rated maximum current should pass through the wire, it will get very hot and might even start a fire.

I was not really "going by" anything, as I had not made any particular decision based on what I had read. I am not sure that it is right to characterise what I had read as rumour, as the information in many cases came directly from people who themselves have one (if I recall correctly, quite possibly on this very thread), rather than having gone through many intermediaries, the information being, among other things, that they could not haul many carriages. However, it is good to know that your examples work well. I have not had any problem with the one that I have had save that it was a secondhand one and the NEM socket had been cut back by the previous owner, which caused some fouling of the non-driving wheel, but that is not a criticism of the design/manufacture of course. I suspect that I may well get one of these new ones so that I have more than one for my planned Southern 00 gauge layout so as to be able to simulate the maintenance routine for the locomotives (i.e., so that the branch train can keep going even when one locomotive is having its boiler washed out), although will probably need to renumber this to something not quite so far west based.

You have had one of the new ones already? Gosh, that was fast. I have one of the original ones, but have not run it much; I had heard not so good things about the mechanism, so it is reassuring to know that it runs well. I anticipate using them only for the two car push/pull trains, so this should perhaps not be an issue in any event.

I had noticed; interesting indeed. I wonder whether the mechanism will be improved at all? The mainland olive green version is a west-country based locomotive, I understand.

That is an impressive building.

All of the stock to which the OP referred would have modern profile wheels, so this is not an issue here.

A back to back gauge is a machined brass item that you put between the wheels: if the backs of the wheels can fit snugly between the brass item, the back to back measurements is correct. You can get back to back gauges from multiple manufacturers; mine, I believe, were bought from Markits. I believe that DCC Concepts also produce some. Do I understand that the wheel circled in red catches on the switch blade? If so, you might try carefully desoldering the switch blade from its current position and moving it slightly to the right. Edit: If, conversely, the wheel circled in red does not catch on the switch blade, but seems to lift upwards when it passes the switch blade, you might instead try filing the opposite switch blade.

You could try first of all checking and adjusting these wheelsets with a back to back gauge. I am not entirely clear as to what you mean by the straight point blade on the through route not providing enough clearance, however, as there is more than one possible permutation of what this could mean. I have often found with these turnouts that, if I do not file the switch blades enough, the track goes out of gauge at the point where the switch rail meets the stock rail and wheels can be forced up and out of the track, causing derailments. Carefully filing the point blades after the points have been laid can solve this. On other occasions, the switch blades can be in the wrong position if not soldered to precisely the right point of the metal attachment points; these can be carefully re-soldered in situ. Use a soldering iron with a small flat tip, either a chisel or a bevel tip of 1mm in size.

Digikeijs does free firmware updates for its products, downloadable over the internet.

One does not need to delete route definitions to get manual control over turnouts - you should be able to control any turnout manually that is not currently being used by an active route (i.e., one that is set for a train to run on it right now) by clicking it in the switchboard window. Make sure that you are not in edit mode, however, or else you will only be able to modify the properties of the turnout, rather than switch it (easily, at least).

I agree with Nigel - for Zimo decoders, the Zimo method of stay-alives is to be recommended, using the Zimo SACC16 charging circuit (for decoders without built-in charging circuits) and multiple 16v 470 micro-Farad tantalum capacitors for the small locomotives (N gauge and small tank engines in 00/EM/P4). The DCC Concepts stay-alives are too large for N gauge and also some of the smallest 00 models; they use super capacitors, which have to be made in a bank because, individually, they are rated at only 2.5v. Super capacitors can give extremely high capacitance, but cannot be made as small as individual surface mount tantalum capacitors. The amount of capacitance in one of the smallest DCC Concepts plug and play stay alive units is enough for most 00 gauge models; only 1-2 seconds of run-on time is needed to maintain reliability.

Incidentally, before I forget, one non-automation thing that I forgot to mention in the last post: if you are using MERG CBus (and this should be sufficient for your needs if you do not intend to automate), you probably do not need a separate DCC accessory bus. This is because there are CBus modules that will deal with all the types of accessories that a DCC accessory bus would normally power. Before committing yourself to this, however, check that you are happy with the CBus controlled alternatives. For example, as to point motors, some types (e.g. the Cobolt Digital IP) are intended to be controlled by DCC and are simpler to set up if they take DCC power as all that is needed is to connect them to the DCC bus. They can be controlled by an IO card (such as those provided by MERG), but that would then need the IO card to connect to the IO ports on the motor as well as connecting it to the (track) DCC bus. However, against that should be balanced the fact that, if you use only CBus, you will not need all the extra wiring of a DCC accessory bus. If you use servo motors for points, it will make little difference, as these will always need servo specific controllers in any event.

I note that you are planning on a 10A 12v power bus. Wires rated for 10A would have to be seriously thick (as in, 13A mains appliance cord thick). If you make your wires too thin and they actually ever end up carrying the full 10A (e.g. under a fault condition) they could overheat and even possibly start a fire. I note that you are planning to use MERG CBus. There is a wide range of kits available for this, and this will allow feedback (including RailCom), but software support is limited. It works well with JMRI, but JMRI is not good for full automation of anything other than a simple layout as it lacks the abstractions necessary to make this workable without scripting so extensive that you are effectively writing a whole application from the ground up in scripting language. If you have indeed finally decided not to automate fully with this layout, that will not be a problem, but be aware of this if you are still unsure on this. In relation to triangulation, triangulation works by measuring the distance between the transmitter and receiver. If you can do this with three transmitters simultaneously, you can get the position of the receiver quite precisely. However, "quite precisely" is on the scale of full sized ships and aircraft rather than small model trains. I am not entirely sure, since I am not a professional physicist, but I believe that it is unlikely that current or foreseeable future technology will be able to measure the minute differences in the time that the (speed of light) radio signals to and from objects a few centimetres apart so as accurately to be able to give them a distance. Even if this were possible, the level of technology needed to do this would be likely to make it prohibitively expensive for model railway use. Given that workable albeit imperfect systems based on dead reckoning exist, it seems unlikely that anyone would try to develop a radio triangulation system for model railway position detection. (If any such thing were to be developed, I suspect that it would be an offshoot of systems for detecting the position of robots or self-driving cars). It is also doubtful whether such a system would actually be any better than what is possible at present, or what might be possible with incremental improvements to current level technology. It would have to be a seriously accurate, highly reliable, easily miniaturisable and fairly low cost system to be better enough than current technology for it to be worthwhile anyone developing it. I cannot be entirely sure of being correct on this (and, unless there is someone here who is in fact a professional data engineer or physicist, I suggest that nobody else can be entirely sure either), but it does not seem very likely that such a system will be developed in any of our lifetimes. If you do want coupling and uncoupling in truly arbitrary positions on a layout automatically, then dead reckoning, combined with DCC operated uncouplers (have a look at Krois couplers) can do this with current technology.

It's a very interesting idea to use triangulation to control uncoupling positioning. Presumably, this would require each feed wire to the layout to know its location and be able, independently and simultaneously, to test its distance to every DCC decoder on the layout, and tell which one is which? It would presumably have to do this to a very high level of accuracy. I suspect that that would be exceedingly difficult to accomplish. Or were you instead imagining using radio transmitters? Such a system would make more sense in the context of dead rail. I am not sure whether it would ever be practical given the large number of items whose position would have to be tracked with millimetre accuracy in a small area, but those who know more about radio frequency technology may have a better idea than I. As noted previously, dead reckoning using good software can give accuracy of about +/- 1cm, which is enough for most purposes, although, in N scale at least, the locomotive does sometimes push back the carriages a few millimetres when coupling.

There are such things as DCC controlled automatic uncouplers, but they are a little marginal with current technology. I looked into them but decided that it would be far easier (and possibly more reliable) for my own purposes to use fixed magnet uncouplers. So long as you are content that you will not want to automate this layout, you should be fine not to install a feedback bus and to use a DCC bus. Whether you want to automate is a matter for you.

I should note that the video hosting platform is now back up, so you can see how dead reckoning works in practice.

Flexible coupling in a station platform can work reliably with dead reckoning - have a look at the "Coupling by Computer" video here for a demonstration (note that the server seems to be down at present so you may have to check back on this to-morrow).

An alternative to block occupancy detection is to use infra-red or optical point detectors. These can be used for full automation, but they have drawbacks - large and visible holes need to be cut into the track bed at multiple points and there are issues with many items of rolling stock not having sufficiently reflective undersides to be detectable without paint based modification. Generally, it is easier to use occupancy detection if one is starting afresh. I should note that dividing track into individual block sections is exactly what happens with track circuits in real life; if you are modelling a real location you can even go so far as to obtain the signalling diagrams and base your occupancy sections on real life track circuits, but it is not necessary to go that far to get automation working. If you are content never to automate, then you can leave out block sections and not worry about a feedback bus, but it will be much more difficult to add automation later if you change your mind. Only you can decide whether you might change your mind. As to LED current draw, I am afraid that I do not know without looking it up - it is likely to vary from LED to LED depending on brightness, efficiency and the values of resistors used (LEDs must always be connected to a power source via a resistor no matter the voltage). There may well be people more knowledgeable on the topic who are able to assist - otherwise, you might compute the necessary current draw by finding the specifications for relevant LEDs online.

If you are going to do computer automation, you definitely need a data bus that can do feedback. I don't know much about SPROGs, I am afraid, so you will have to investigate this, but if you think that you ever want to do computer automation, you need to be planning right from the start to have block detection and feedback, both in how you set up your track feeds to insulate at the right points and how you set up your data 'bus to be able to get the feedback back to your command station and then onto the computer. As to LEDs - LEDs vary, so you will need to check the amperage for each and multiply it by the number that you need, allowing a margin of error.

I do not know about SPROG systems, so cannot advise on whether you need busses 7 and 8. I do not think that you need buses 5 and 6 - bus 3 should be able to deal with this if it has sufficient amperage. If you need to distinguish between different lighting, local switches powered by your communications bus would be better than lots of different power buses. Bus 4 is only necessary if you actually have 16v AC accessories. I am not aware of any, but you might have some. You may wish to consider whether 12v DC versions of such accessories can be procured to eliminate bus 4 entirely. Make sure that all of your wiring is rated for a current no less than the maximum current that the power supply supplying that wiring, as limited by protection devices such as fuses, can supply. For my own layout, I use the LocoNet bus instead of a DCC accessory bus, as this is a better general communication bus and is capable of two way communication, which is important for feedbacks. If you do not need any feedback (e.g. block occupancy) and will never need this in the future (e.g. for computer automation), a DCC accessory 'bus will suffice, but, if you have not already considered this carefully, you might want to give thought to an alternative data bus.