Which power supply?


rbwhale

Member
Hello Everyone:
I am building a 40 by 82 inch N scale layout that will will fold up against our study wall. The layout will use 2 inch high density foam and, due to the need to allow some height for mountains, there is only 2 inches to spare in the bottom, which will be covered by a thin sheet of plywood, which means any power supply has to be less than two inches thick, although the other dimensions are not so important. This necessity of covering up the wiring in the bottom is a mandate laid down by my lovely and patient wife, aka She Who Must Be Obeyed. The plywood Birch, probably) will be removeable, of course.
The layout will have 5 Kato #6 remote turnouts, one Kadee electromagnetic decoupler, and 6 or seven LEDs in my houses. (it's a mainly rural scene, since 40 by 82 does not leave all that much room for a lot of buildings without, IMHO, looking crowded.) I have two questions: 1)how much wattage and amperage will I need and 2) many of the power supplies listed on Amazon are called "LED Drivers" and used to power strings of LED lights outdoors. Most of them have wattage ratings of between 60 and 200 watts, and most are less than 2 inches thick. Would something like this be suitable, or are there better alternatives that I'm not thinking of?
Thanks,
rbwhale
 
What I want to know is: Are you going to remove all the engines and cars every time before folding it up, place them somewhere, then have to re-rail them every time you lower the bench/trackwork back down ?! And, unless securely anchored there probably will be structures you'll need to remove each time, as well. Did you take this into account ?
Far as control, DCC is smaller and less bulky than an analog powerpack and all the block wiring it needs for train independency ..
 
What I want to know is: Are you going to remove all the engines and cars every time before folding it up, place them somewhere, then have to re-rail them every time you lower the bench/trackwork back down ?! And, unless securely anchored there probably will be structures you'll need to remove each time, as well. Did you take this into account ?
Far as control, DCC is smaller and less bulky than an analog powerpack and all the block wiring it needs for train independency ..
Yes I have considered weight. The benchwork on the layout uses special light plywood, the structures will be well anchored, the hinges are quite strong, anchored in 3/4 hardwood screwed to the studs with #12 screws. I will remove the cars each time I fold it up, but I don't really need to have that many on a door sized layout. Since this is the only place in our small house I can put it, our garage being my studio and chockablock full of tools and benches already, this is a small inconvenience (compared to the 150 foot G scale railroad I had in California!). At least in Oregon winters I'll be warm and dry.

I may no have been clear: the layout will be DCC, but the switches and LEDs require DC; DCC will not work according to what I've read. But thanks for posting.
 
I didn't ask you about weight...
Anyway, since you say you have a garage I wonder if you couldn't clear a space for a 'door sized' layout in there without having to have it fold up; tools and all underneath it and shelves/cabinets above it...I'm just getting at folding it up could become an albatross..
 
I think what were' talking about here is that a fold-up bench will have to be both easy to lift, well out of the way, easy to set up, and easy to 'de-commission' at the end of a session when you decide it must be folded back up out of the way. Your scenery will have to be able to withstand the change of angle/gravity, and any items that could fall or slide off will have to come off....cars, engines, structures, some trees (?), and so on...

It's one caution that follows the members in so many hobbies: the more heavy, large, cumbersome, awkward, complex, unreliable, and/or poorly planned something is, the less likely it will survive beyond six months of use. In Astronomy, it's large and heavy telescope tubes or their mounts, as an example. There's determination and 'youthful enthusiasm' at first, probably the first ten or fifteen times you have to horse them into your station wagon or car trunk, plus the observation recording table that doubles as the repository for your eyepieces and other accessories. When you arrive at your destination, in Farmer John's dark field about 20 miles out of town, you have to reverse the process. Then, at zero-dark-thirty, you having gotten thoroughly tired and cold on this, the 12th of January, you must pack it all up again, drive home, unload yet again, and try to get four hours of sleep before the kids are up.

Been there.

About the power requirement....add up the LED's based on their specs, and the power supply should have the requisite voltage, perhaps necessarily snubbed via a substantial resistor so that the LED's don't have a shortened life. For LED's, just a dozen or so, I can't see you needing more than a single amp, probably much less. We'd be talking maybe 10-12 watts of power in total. I hope an electrician/technician/engineer pipes up and sorts it out for you.
 
I think what were' talking about here is that a fold-up bench will have to be both easy to lift, well out of the way, easy to set up, and easy to 'de-commission' at the end of a session when you decide it must be folded back up out of the way. Your scenery will have to be able to withstand the change of angle/gravity, and any items that could fall or slide off will have to come off....cars, engines, structures, some trees (?), and so on...

It's one caution that follows the members in so many hobbies: the more heavy, large, cumbersome, awkward, complex, unreliable, and/or poorly planned something is, the less likely it will survive beyond six months of use. In Astronomy, it's large and heavy telescope tubes or their mounts, as an example. There's determination and 'youthful enthusiasm' at first, probably the first ten or fifteen times you have to horse them into your station wagon or car trunk, plus the observation recording table that doubles as the repository for your eyepieces and other accessories. When you arrive at your destination, in Farmer John's dark field about 20 miles out of town, you have to reverse the process. Then, at zero-dark-thirty, you having gotten thoroughly tired and cold on this, the 12th of January, you must pack it all up again, drive home, unload yet again, and try to get four hours of sleep before the kids are up.

Been there.

About the power requirement....add up the LED's based on their specs, and the power supply should have the requisite voltage, perhaps necessarily snubbed via a substantial resistor so that the LED's don't have a shortened life. For LED's, just a dozen or so, I can't see you needing more than a single amp, probably much less. We'd be talking maybe 10-12 watts of power in total. I hope an electrician/technician/engineer pipes up and sorts it out for you.
Thanks for the thoughts, but I have considered this carefully. I'm a sculptor who had to make a studio out of his garage when we moved from the 10,000 square foot facility I was able to use for the last 10 years to Salem , Oregon. We could only afford a small house and the garage, while reasonable sized, is crammed full of what I need to sculpt and there is not a two foot length of free wall available, let alone 7 or 8 feet. Your comment about large telescopes rang a bell: I owned a 16 inch Dobsonian for years which was so cumbersome I had to build an observatory for it, which worked quite well. I, in essence, brought the farmer's dark field to my backyard, with a roll top roof. A back injury put an end to that, unfortunately: the roof was quite heavy and I could no longer manage it easily. So, been there as well and that is why I've planned the layout so carefully. The layout will also feature a couple of gas struts to make raising it easier, so it should not take much oomph.

The layout will weigh less than 40 pounds, and it will fit nicely on the only free wall in our house. Scenery, trees, and houses will be rock solidly mounted, and I will not have to fold it up every night, only when we need to get under it to get something, so I do not believe it will be up and down every day.

You did not mention the 5 #6 Kato remote turnouts or the Kadee electromagnetic decoupler which, I am guessing, may take more than one amp, but I don't know how to figure the power requirements for those. Do you have any idea that might get me in the ballpark?

Thanks for the astronomical history, by the way. I actually met John Dobson a couple of times in San Francisco. One of his favorite phrases "It's a disease!" comes to mind whenever I think about him. It really brings back memories.
 
I have a layout which is stored vertically when not in use, 7'6 X 4' and its in two half's more for practicality than anything else, power wise two wall warts are sufficient, one powers my DCC controller and 8 end of line buffer lights (wired into the buss line)
As for lighting, why would you need a driver and for so few LED's, unless you intend to use a string as overhead lighting, for the layout the LEDS need to be no more than 3amp and most either come pre wired with a 12v resistor or you need to solder them on yourself.
I use a simple distribution board for my lighting so they can be wired to switches and turned on/off as I want, (my street lights are grouped in 3 sets of 5 and one of 7) plus 5 building lights, I also use a CDU for my turnouts, which gets power from a separate wall warts, but it does power 2 double turnouts and 9 single ones (OO scale Peco surface), probably an overkill on my part I reckon, I could run it from the main DB, so far, after two years, no problems or fires.

There are somewhere, posts of my layout all lit up.

There is a formula you can use to work the power out, but I can't find it at the moment.

As for covering up the bottom, I'm assuming you mean the underside of the board, a friend of many years had a similar problem, his wife was not happy with all the wires being visible, when they layout was raised, so he used some plywood to cover it up, wife still not happy, she came home one day to find his pride and joy was no longer there, and had been replaced with some pictures, and a small cabinet with his trains inside, it took her over a week to work out that it was indeed, still there, he had cleverly matched the wallpaper onto the plywood and added the pictures and cabinet to that, so it looked like the wall behind it. 🤣
 
Maybe overkill ... I use old PC power supplies. Ton of current avail, +-12VDC, +5VDC; note that if you get one and modify, you can weld with it - 25 to 30A avialable, so be cafefull!
 
Maybe overkill ... I use old PC power supplies. Ton of current avail, +-12VDC, +5VDC; note that if you get one and modify, you can weld with it - 25 to 30A avialable, so be cafefull!
I'm pretty sure he wants to run a N scale railway, with that kinda power, he's likely to run it at supersonic speed, at least for a second or two 🤣 🤣
 
Maybe overkill ... I use old PC power supplies. Ton of current avail, +-12VDC, +5VDC; note that if you get one and modify, you can weld with it - 25 to 30A avialable, so be cafefull!
It has to be less than 2 inches thick to fit under the layout. I have an ESAB 235 with which I weld I/2 inch plate at 220 amps, so I'm well aware of the dangers! I am beginning to think that a 12 volt, 100 watt power supply supplying 5 amps should be sufficient, since only one switch, or Kadee electromagnetic uncoupler will will be activated at a time.
 
I have a layout which is stored vertically when not in use, 7'6 X 4' and its in two half's more for practicality than anything else, power wise two wall warts are sufficient, one powers my DCC controller and 8 end of line buffer lights (wired into the buss line)
As for lighting, why would you need a driver and for so few LED's, unless you intend to use a string as overhead lighting, for the layout the LEDS need to be no more than 3amp and most either come pre wired with a 12v resistor or you need to solder them on yourself.
I use a simple distribution board for my lighting so they can be wired to switches and turned on/off as I want, (my street lights are grouped in 3 sets of 5 and one of 7) plus 5 building lights, I also use a CDU for my turnouts, which gets power from a separate wall warts, but it does power 2 double turnouts and 9 single ones (OO scale Peco surface), probably an overkill on my part I reckon, I could run it from the main DB, so far, after two years, no problems or fires.

There are somewhere, posts of my layout all lit up.

There is a formula you can use to work the power out, but I can't find it at the moment.

As for covering up the bottom, I'm assuming you mean the underside of the board, a friend of many years had a similar problem, his wife was not happy with all the wires being visible, when they layout was raised, so he used some plywood to cover it up, wife still not happy, she came home one day to find his pride and joy was no longer there, and had been replaced with some pictures, and a small cabinet with his trains inside, it took her over a week to work out that it was indeed, still there, he had cleverly matched the wallpaper onto the plywood and added the pictures and cabinet to that, so it looked like the wall behind it. 🤣
From what I'm hearing here, and in your post, is that a 100 watt 5 amp power supply should be sufficient, since even the highest current draw, the Kadee electromagnetic decoupler and the turnouts are only activated one at a time. Posts on the N scale forum agree that the turnouts need a little bit less than one-half amp and the current hog, the Kadee decoupler, around two amps. Does this make sense?

Happily my always patient wife also like to play with trains and is fine with plywood, as long as it has pictures attached.
 
From what I'm hearing here, and in your post, is that a 100 watt 5 amp power supply should be sufficient, since even the highest current draw, the Kadee electromagnetic decoupler and the turnouts are only activated one at a time. Posts on the N scale forum agree that the turnouts need a little bit less than one-half amp and the current hog, the Kadee decoupler, around two amps. Does this make sense?

Happily my always patient wife also like to play with trains and is fine with plywood, as long as it has pictures attached.
Yeah, that would be enough for what you are describing. couple of things you might want to consider tho'.

I'm assuming your controller has a separate power supply, so when wiring your lights, use a distribution board, they are cheap and height wise, well under your 2" height requirement, the reason is simple, if you at a future date decide to add more lights, or any other equipment, much easier to install, also, as I found out, all my lights were too bright, and instead of having to remove the resistors on 22 lights and solder larger ones instead, I just added a larger resistor between my main DB and each DB for the 4 sets of light, so only needed to do 4.

I would also use a separate DB for your turnouts, I suggest this as although the power draw is low, turnouts do tend to slow down over time or fail to switch across correctly, causing derailments if you use a DB, you can, if needed, add a CDU (you'll have to look around to find one the size you need) to the circuit with little extra wiring required, the CDU as it stores the power and release in a momentary burst "kicks" the motor giving it a positive action on the turnout, also if the turnout motor jams it prevents burnout of the motor as the power is momentary, so once it's used it's gone. The one I use is larger than your 2" height, but if I could, it will switch all my turnouts at the same time, plus at least half dozen more.

I'm glad your wife likes to play with trains, and is happy with a few pictures, but I wouldn't suggest anything with a train on it. 🤣

Let us know how you get on with your build, and a few photo's would be good too, see how it all comes together, if I can help, you can always PM me, or just ask on the Forum, always somebody around.
 
Much appreciated. I'll take your advice about the distribution boards, and I am going to use the separate power supply to handle the lights as well.

I can't tell you how much I depend on a forum like this: the wisdom of crowds is invaluable in model railroading.
 
Much appreciated. I'll take your advice about the distribution boards, and I am going to use the separate power supply to handle the lights as well.

I can't tell you how much I depend on a forum like this: the wisdom of crowds is invaluable in model railroading.
We're all happy to help, I'd be right up the creek if it wasn't for forums like these, I knew nothing about DCC, don't think I know much more now 5 years on. 🤣 🤣
 
Last edited:
Ah, a fellow former astronomer. Although, can anyone really be a former anything after a sizeable excursion into a hobby? Even Scouts, cyclist, they're all forever part of who we are. I'm happy you are on top of all of this. We sometimes come across as overbearing in this hobby due to the complexity and myriads of pitfalls, but we at least mean well. :cool: I sincerely hope you have a blast, and that what you create meets your highest expectations.
 
Ah, a fellow former astronomer. Although, can anyone really be a former anything after a sizeable excursion into a hobby? Even Scouts, cyclist, they're all forever part of who we are. I'm happy you are on top of all of this. We sometimes come across as overbearing in this hobby due to the complexity and myriads of pitfalls, but we at least mean well. :cool: I sincerely hope you have a blast, and that what you create meets your highest expectations.
Thanks.
 



Back
Top