cliff park

A little GPO story. Many years ago, when telephones and Royal Mail were all GPO, a local Telephone overhead gang had to renew a rotten pole, which had a post box mounted on it. So they contacted the local postmaster to send someone with a key as the hoops which held the box on had nuts on the end inside the box. By the time they had disconnected the dozen or so telephone lines and got everything ready to go no key had turned up. So the decision was made to fell the pole, saw it off just above the post-box and knock the hoops upwards to remove it. Slide the hoops onto the new pole, place in ground, add steps, arms, reconnect all the customers, great. It was only as they drove away they realised because the new pole was slightly thicker the letterbox was now ten feet off the ground.

Don't forget that an ammeter is in series with the supply. So if you feed the ammeter through a bridge rectifier then the supply downstream of that will always be one way, you would need another reversing switch after the ammeter. Digital meter sounds the way to go. How about two 4mm sockets in one leg of the feed, plugging the meter in, in current mode, would read whichever way the current is flowing. You could then bridge the two sockets, short link of wire with a 4mm plug on each end, and remove the meter completely for use elsewhere when not required.

One point that has always struck me is when photographing anything moving, or in the case of a model vehicle, potentially moving, the subject should look like it has somewhere to go. So for the two photographs of the goods train, photo 1 looks like the train is moving into the space on the right hand side, whereas in the second picture it is going to run out of track. I'd be a little worried about your photographer friends, if they become very good you could be out of a job.

I think this last drawing contains a serious error. When the switch is to the left the rails are connected to one leg from each controller, and similarly the other way.

Don't forget that thatch has incredible insulation properties. If it could be reliably fireproofed and not need replacing regularly it would be the best roof ever.

I think he might be winding you up, a BLT in model railway terms is a Branch Line Terminus.

Two thoughts:- you do realise this is not a mains unit, you would need a transformer as well;- you can get round the instantaneous load problem (which could also cause protection problems) by using a capacitor discharge unit. These also protect point motors.

Like this :-

It's no good, I have to be the bearer of bad news. I was hoping KNP would spot it and save me from this. The strut on the inside of your personnel door goes the wrong way. My dad, a builder said the easy way to remember is hangman . See my sketch. The strut should be supporting the otherwise unsupported rail.

Reed switches and Hall effect are not the same thing, which your heading implies. Hall effect switches are solid state, like a transistor, which is switched by a magnetic field. Most reeds are a simple make , so to achieve a changeover you would need a relay. Hall effect switches would need a relay to switch the kind of voltages and currents the frog needs.

Thought you may like these, top of a house in Walberswick, suffolk

By the way it matters not a jot which leg of the LED the resistor is wired in. It may be convenient if they are all wired the same when it comes to fitting them, eg negative feed always go to the resistor leg, but from an operational point of view it doesn't matter.

Google Alfred camera. It is free , downloadable software that forms the link between your wi-fi and the camera and enables any other device to see the pictures, with appropriate passwords etc.

It is possible, just, to see Norwich castle from the station car park. It does depend a lot on the time of year as the leaves on the trees obscure it in the summer.

Sorry to be a pain, but it's the 'unread content' links at top and bottom right of page that takes me to my followed pages, and they still don't work.

My problem is the same but with 'Unread content' . Totally inaccessible all day today. Windows 10, Chrome, 60Mbs broadband. But error code 524 specifically says error at the server end.

In normal, non-model railway use, a switch is used to switch something off and on. In other words make or break a current. This applies to the CDU/point switch. It is also true that the point switch will always be making to pass a high current, but when it breaks there is negligible current, and with DC it's the break that causes more problems. In this respect the use of a CDU is a big advantage. In most other areas the switch does not make or break any current, it is thrown when no current is flowing. The rating is almost irrelevant. It is however generally true that a higher rated switch will be more robust mechanically, and probably better made. You pays your money and you takes your choice.

The fact that the LEDs are in parallel makes no difference. Each LED is across the supply. The fact that there are others makes no difference. If the bulbs light, even dimly, this would suggest the LEDs are short circuit. Try an LED with resistor in series, say 1KΩ, straight across the 12V supply, it should light. If it doesn't reverse the LED connections. If it still doesn't it's dead. You surprise me with the 30mA figure, is this the LED spec.

There are masses of 555 timer circuits on the net, which would run quite happily off your LED supply and cost pennies. A few set at different intervals connected to LEDs in different buildings would look quite random.

Don't forget the bulb. Take a car brake light bulb, attach a short piece of wire to one terminal. Turn up the controller, sit one terminal of the bulb on one rail and the wire on the other. It should light up, or at least glow. move it to random different places around the track, or slide it round the whole layout. You will soon see if there is any resistance, and can pinpoint it quite accurately. The bulb draws enough current to be very effective.

This is the profile I make using a router. Obviously the grooves need to be the thickness of the panel at top and ply/hardboard whatever at bottom. Length is perimeter of panel plus extra for mitreing. One end or side is held in by screws, and the cable goes through this side, then that side, panel and cable can all be removed together to work on the panel.

Do you have access to woodworking tools, specifically a router ? It is vert easy to make a wooden box with grooves for the panel. And cheap

Sorry, I just made the numbers up for a reference.

I have drawn how I think it works. Obviously it doesn't matter which switch is used for which function. I haven't drawn it but for the pedantic there should be a dotted line linking the levers to show they are mechanically 'tied'. ie work together. I have drawn in LEDs assuming the second pole of the switch would be used for indication.

A capacitor can never charge, as such, on AC. If it is non-electrolytic it simply charges and recharges in each direction with each cycle. If electrolytic it will most likely just go bang. (We had a contractor who accidentally connected a large electrolytic in reverse, it went bang and covered him in the yellow liquid. His face retained a yellow tinge for months and he was for ever more called Nanky Poo)