First, welcome to the MRH forum.

I agree with the decision to use a dedicated supply for your lighting and accessories.  Regarding the supply, a 3-5 amp supply will have plenty of load capacity for all of your LED's and likely any other DC devices you might want to install but do keep current draw in mind when adding accessories to the layout.  As a rule I try not to go beyond %80 of the maximum load for a supply.

LED's typically require somewhere between 15 and 30 Milli-Amps to illuminate depending on size type and manufacturer.  You will want to know what yours are drawing so you can anticipate the load.

What voltage will the power supply provide?

A lab supply will likely have over-current protection built in but having additional fusing or circuit protection never hurts.

An accessory buss of say, 16 gauge wire running around the frame of the layout should be able to safely provide all the power for your needs, but again it depends on the anticipated load. Be safe rather than sorry.  From that buss, I would advise using some sort of screw terminal blocks to distribute power to the various lighting circuits and accessories.  You may want to switch each building or accessory separately, I don't know but think about that ahead of time too.  The feeders from the buss to the buildings etc. can be lighter gauge wire as they will likely be fairly short runs.

For a small Christmas layout I might even consider fiber optics for lighting.  While tedious to install in the buildings, fiber can simulate rows of multicolored Christmas lights using only a few different color LED's, centrally located.  If you are interested in Fiber, check out the Fiber Optic Store.  I have purchased from them in the past and found the service to be good.

A previous issue of MRH contains an article by Charlie Comstock that discusses LED lighting.  In the article Charlie explains how to build a voltage regulator for supplying LED's, IIRC.  I don't have my collection handy so I can't say for sure which issue it was.  Maybe issue 7?  Perhaps someone else will remember, or I'll have a look for it later.

Edit:  Remember LED's are polarity sensitive, ie: they won't work if wired with reverse polarity.  LED's in series are best if they are of the same type and specs, IMO.  LED's in Parallel should each have their own resistor so wiring in series makes more sense, IMO.  The nice thing about LED's in series is they will all illuminate with the same amount of current, providing there is enough supply voltage, about 2 volts per LED in the circuit.  To put 6 LED's in 15 buildings you will need to wire each building as a series circuit in parallel with your supply.

Here's a handy array calculator that you might find useful to determine resistor values needed etc.

LED Array Wizard

Hi blue,

Thanks for the welcome and definitely thanks for the quick and comprehensive response. Much to think about.

Not sure what voltage to apply, but I'm thinking maybe 12v in case some of the servo devices I look at are up there, so PS voltage output rating should be 18v at least.

Where would you put the fuse? On the + side near the PS terminal and before the first circuit of LEDs? As I take your suggestion, use no more than 80% of rated output current of the PS.

The set will be disassembled, breaking the base into 3 sections, and removing the buildings. This is necessary given where it is stored for 11 months. Loading it up with weight and fragile things just won't work.

So, I will need to connect the buss in at least two places  when I assemble it. Terminal blocks on either side of the joints would work for the connection and extra spaces for the accessories. I'm thinking I should run the buss down the middle into terminal blocks on the inside of the frame of each section.

I will also need to connect each (series) building circuit (parallel) to the buss each time I assemble it too. As I select the LEDs for colour and brightness for each building, I will secure them in near windows. I will also add the resistor somewhere in the building too.

I looked at the fibre optics link. Intriguing! I've never used optics so I do not have a feel for it at all. Given that each building will be 'connected in' each year, which do you think would work better, price, complexity, etc., LEDs or fibre optics? In any case, there is potential for future projects there.

Whew! Loads o' fun!

Neat wizard for calculating LEDs circuits. I will definitely be using it.

B.

PS. Your pic with the shades was taken last year right? No sun this year in your neck of the woods with our BC fires shading the sun! Sorry 'bout that!
 

Well, we've had plenty of our own forest fires this year, too.  I work in northern Saskatchewan and we had no fewer than 6 fires burning within 20km of our site.  One actually came onto the property and burned trees next to our airstrip.  But we can definitely blame you guys in BC, too.   

Fiber optics can be very cheap.  I still have several packages of strands taken from a light bright or some child toy. These show up here and their.  All that is required is a black box to hold the bulb, push the fiber optics thru a hole in the box. route then to the buildings windows. 

You can flare the end by holding it up to a soldering iron or any source of heat. Makes a good difuser for a larger spread of light.  if you8 are inginous you can have lights changing color with a rotating color filter paper or film.   The size of the fiber is  small enough to look more scale than leds unkless you use SM led.

This is what I use on tender rev lights also. One small strand, heated to make a lens, the LED is in the tender shell

Marc Fournier, Quebec

Not sure what voltage to apply, but I'm thinking maybe 12v in case some of the servo devices I look at are up there, so PS voltage output rating should be 18v at least.

I was thinking 12 volts too.

Where would you put the fuse? On the + side near the PS terminal and before the first circuit of LEDs? As I take your suggestion, use no more than 80% of rated output current of the PS.

I would probably fuse the positive lead between the supply and the beginning of the accessory buss wiring.  Yes, I would only load the supply to %80 of the rated output current.

The set will be disassembled, breaking the base into 3 sections, and removing the buildings. This is necessary given where it is stored for 11 months.

Right!  Sorry, I was thinking of it being a permanent layout installation but it is all still feasible if done with dis-assembly in mind from the start.

So, I will need to connect the buss in at least two places  when I assemble it. Terminal blocks on either side of the joints would work for the connection and extra spaces for the accessories. I'm thinking I should run the buss down the middle into terminal blocks on the inside of the frame of each section.

I would definitely use terminal blocks for connecting the lights but I would be tempted to us 2-conductor keyed quick disconnect plugs for the disconnects in between sections.

I looked at the fibre optics link. Intriguing! I've never used optics so I do not have a feel for it at all. Given that each building will be 'connected in' each year, which do you think would work better, price, complexity, etc., LEDs or fibre optics? In any case, there is potential for future projects there.

Yes, fiber optics are very cool.  In your case you would want the buildings to house the light source and the fiber to route to various locations within a building.  This way you can still disconnect the wiring and remove the building, leaving the fiber optics in place.  Fiber does have some limitations when used for model railroad lighting but there are ways to work around some of them.  One way is as Marc suggests.  By heating the end of a fiber optic filament you can "mushroom" it to give a more diffuse light with less of a spot effect.  Also, as Marc mentions there are many sources for fibers on the cheap.  One fiber optic Christmas tree could be a lifetime supply of small filaments.

Since you are comfortable with LED's and not familiar with fiber optics you might want to save fiber for the future?

PS. Your pic with the shades was taken last year right? No sun this year in your neck of the woods with our BC fires shading the sun! Sorry 'bout that!

Actually that picture was taken back in February of this year.  It was like -30 C or -22 F, but so sunny that with all the reflection off the snow I had to wear shades in order to avoid squinting (light sensitive eyes).  The Picture was taken in Moose Jaw, SK. near the CN yard.  Really the fires burning here are just a drop in the bucket compared to what is going on in B.C.  No apologies required in any event since my mother-in-law, who lives in Vernon, has already apologized for smoking us out once this summer.  The rest of the time it was thunder clouds blocking out our sunlight.  Darn wet cool summer for what is normally "drought" country! 

Hmmm... why am I craving smoked salmon right now? Oh well, back to the train...

Okay, LEDs it is and Optics for a future project. In fact with the layout wired for 12VDC, not only could I add optics I may even convert certain buildings. I've asked my wife if I could add optics to the ceiling in the kitchen above the counter where the train is set up, but she said that wouldn't be necessary.

Next step is to purchase a PS and start experimenting with a few circuits then wiring the buildings. I'll wire the buss when I take the base out in early December.

We are also working on the first 2 dioramas, with snow, trees, grasses, people. We experimented with making conifer trees and grasses earlier this year. We are inspired by having found a model train display in Osoyoos while attending my son's wedding. I'm not sure of the rules/etiquette here yet, so I won't put the URL, but search 'model train osoyoos' to see what got us going early this year. Unfortunately, we only had 2 hours of viewing time.

Thanks all, for your help. I'll be back with other questions as the electrical and diorama projects continue, and I'll try to contribute where I can in return.

B.

Right trains...train loads of Salmon... [grin]

I've asked my wife if I could add optics to the ceiling in the kitchen above the counter where the train is set up, but she said that wouldn't be necessary.

An Electrician I used to work for built a home theater room in his basement that has a starlight ceiling done with fiber.  It was neat, but overkill.  Too much time and money on his hands I think.

I'm not sure of the rules/etiquette here yet, so I won't put the URL,

URL's are fine, but we prefer they railroad related and family oriented of course.  We also really like pictures here so if you can, do take some and put them up, as your Christmas layout come together.

I would suggest using some sort of multi-pin connectors for all of the electrical connections between sections.  I would separate the track connections into a separate two pin connector, and the rest of the wiring into connectors having as many pins as needed.  I think undoing screws for the wiring and then replacing them every year would get tiring, especially with the rest of the work you would do with your holiday decorations.  In addition, the more often you undo and re-install a screw, the more chance you have to strip the screw or mangle the head.  One other tip, if you are running bare wire under a screw and tghtening it down, solid wire will work best for the buss, but you want stranded wire for any "pigtails" like the wires from the main buss to the plugs.  If you use stranded wire and need to fasten it to a screw, strip a 1/4 inch of insulation off the end where it goes under the screw and then use a little flux and solder to make the end of the stranded wire into solid wire.  If you don't make it a solid wire where it goes under the screw, the individual wires will push out and you could end up with a connection where only one or two small wires are actually carrying current.

Again, thanks so much for your responsees. I have the plan; just need to spend the $ and time now, but wait,...Murphy lurks somewhere... as usual

Here is the URL to the Osoyoos, BC Desert Model Railroad web site.

http://www.osoyoosrailroad.com/

When I drove into Osoyoos, BC, on the west side of town on HWY#3, last week I noticed a sign on top of a building in a commercial complex: Dessert Model Railroad. Having a few hours to kill on Thursday my 84-year old Dad, my wife, and I checked it out. Frankly, it was the highlight of the trip. Seen many weddings before, but never anything like that. Dad worked the rails after the war, along with my Grandfather and uncles, so he was completley enthralled with the detail as were we all. Wow! We needed the whole day, but could only give her 2 hours.

Husband, wife, daughter team have been working on this for 10 years. They recently completed 4000 sq ft and were talking about starting over at the begining to 'renovate'. It is in a warehouse with an office and a store in addition to the layout on the second floor.

Check out the videos on their site. Some were filmed a few years ago, and the project has evolved much further than indicated. Enjoy, although I suspect some of you are similarly talented within your own space.

B.

You are most welcome.  Ask questions anytime you need to, help out where you think you can, and don't forget to take a picture of your layout when it is up this Crhistmas so you can show us what you are doing!

I did google the Osoyoos Railroad and would like to see it too.  Maybe next time we visit family out that way.  Thanks for the heads up and the info.