Crosland

Direct from China? That's your problem. Buy a UK brand like PowerPax. Even though they may be made in China they will be well specified and tested. See http://www.edn.com/design/pc-board/4441830/Teardown--12V-AC-adapters---The-Horror

That was only one suggestion. General purpose switch mode DC supplies are widely available and will not cause any issues.

It regulates the voltage but the controller does NOT vary the current. The load (the loco) determines what current is drawn, not the controller. The alternative (resistance) controller has a relatively high resistance and forms a potential divider with the loco. It doesn't regulate either current or voltage in any meaningful way.

And the EZ Command What insurance consequences? We are talking about a DC power supply with all the relevant CE marks, etc.

You could use a variable voltage regulator such as the LM317, which has built in overload protection.

Most DCC kit will work on DC. The AC DCC signal is always created in the command station, it is not related in any way to the mains AC.

A company like Bachmann really ought to know better. You contract is with the retailer. If the goods are fault, they are faulty, and the retailer is responsible, End of. No manufacturers warranty can trump the law of the land.

As a business I have sent literally thousands of parcels by Royal Mail to all corners of the world, only a very small percentage were signed for or tracked. I can count the losses on one hand. Most of the "lost" parcels have been returned after three or four months, one via a remote pacific island according to the postmarks! The service simply cannot be faulted for what it costs and the speed and reliability of delivery.

It's worth remembering that the energy stored in the capacitor is proportional to the square of the voltage. Increasing the voltage by around 50% would be equivalent to doubling the capacitance. There's always a trade off somewhere, however.

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That's what is meant by poor regulation. Much the same as a transformers output will vary with load whereas a regulated supply will not. All down to the quality of the regulation. A resistance controller as a very high source impedance and cannot regulate the output voltage as tightly. It is still trying to control the voltage but as soon as you draw any current the controller's resistance causes a voltage drop, reducing the voltage available at the output. Again, just artifacts of poor regulation v. good regulation. That's just muddled thinking. Apply ohms law and you will understand what is going on.

No, they all vary the output voltage, subject to a maximum power output. What you are describing is the difference between a crude controller with poor regulation and a decent controller with internal feedback that provides good regulation.

All conventional model railway controllers are voltage controllers in one form or another. They control the voltage at their output. Voltage drop occurs due to resistance in the layout (wiring and trackwork). No controller can compensate for that unless it monitors the voltage at remote point of the layout. The only way would be to raise the output voltage affectin operation closer to the controller.

It's better to add boosters and divide the layout into power districts if you need more power than one large booster built into a command station can supply.

Not from a single output. Three Amps is easily doable with large reservoir caps, linear regulators and lots of heatsinking. Personally, I wouldn't bother, just buy suitable item(s) off the shelf.

Do you know they definitely support service mode programming? Do they have the necessary components to mimic the acknowledge current pulse from a loco decoder?

Not a good idea, IMHO. Graphite is used as a lubricant and this will reduce friction between the wheels and rails.

That's 100 ohm. It's 1, 0, 0 and 0 multiplier following the usual resistor code, but with 4 digits. 1K would be 1001, or 102 in 3-digit code.

PayPal generally has (or used to have) a condition that you could not charge more for accepting PayPal, but it didn't stand in the UK as surcharges were legal for other payment types. It's a long time since I have come across any sellers charging extra for using PayPal or offering a discount for not using PayPal, so I suspect the real impact will be slight.

No. A 21W bulb rated for 18V will dissipate 21W and limit the current to 1.16 A, if there's a dead short with an 18 V supply. No harm will result to anything that was fit for purpose in the first place. A 21W/12V bulb (implying a hot filament resistance of 6.8 ohms) with 18V across it will attempt to dissipate 47 W and will probably blow, if there's a dead short with an 18 V supply. The idea of using a bulb instead of a fuse is that you do not need to replace the bulb after every short. It's simple application of ohms law V=I*R and power = I*V. With a transistor controller some form of fast electronic cutout or current limit is to be preferred over thermal. It's very easy to arrange as part of the base drive to the output transistor. There are lost of circuits available. MERG used to have some on the public part of their website, worth looking there. Laptop supplies have very fast overload protection and would be ideal if it were not for the high output voltages for MR application. A 12 - 15V switch mode supply is preferable except for those circuits that rely on the 100Hz from a rectified but unsmoothed supply.

Apart from the bit about it destroying itself

Some interesting information on the NCE website "The Power Cab has built in overload for basic self-protection that will continuously try to reset until destroyed if left uncorrected" I am sure that's not what they really mean... And https://ncedcc.zendesk.com/hc/en-us/articles/202353725-Why-do-I-need-a-breaker-Myth-vs-Fact

No it doesn't. Not to any meaningful degree if those components were fit for purpose in the first place. Please explain the mechanism by which a DCC dropper wire will fail. Why would you have a polarity switch on a DCC layout? NO thermal cutout is EVER appropriate for DCC use. Why would you use more than one Powercab?

Better price, and in stock, at Coastal DCC http://www.coastaldcc.co.uk/products/bachrus/ I must declare an interest as I have a business relationship (as a supplier) with Coastal.

Yes. It is almost certainly switch mode. Why do you think it isn't?