If the load isn't too high you can use "wall warts." You can get them up to 1.5 amps. You could use more than one and divide your lighting into sections. You can also purchase a 12 volt power supply at any electronics store or mail order, and even Radio Shack sells them. You can get power supplies with capacities of several amps.
..... Bob
Beam me up, Scotty, there's no intelligent life down here. (Captain Kirk)
I reject your reality and substitute my own. (Adam Savage)
Resistance is not futile--it is voltage divided by current.
I use Radio Shack transformers for auxillary power supplies.
http://www.radioshack.com/product/index.jsp?productId=2102702&cp=2032058.2032230.2032277&parentPage=family
http://www.radioshack.com/product/index.jsp?productId=2102700&cp=2032058.2032230.2032277&parentPage=family
You could also use something like this:
http://www.radioshack.com/product/index.jsp?productId=2194437&cp=&sr=1&origkw=power+supply&kw=power+supply&parentPage=search
Rotor
Jake: How often does the train go by? Elwood: So often you won't even notice ...
MVRail,
Or, you can use an old DC power supply/transformer and "dial it down" to the voltage that you need. You may want to add a physical stop to it so that no one accidentally turns it up and blows out your lights.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
I have an accumulation of old train set power packs (garage sale prizes, collected by my sister,) wall warts from dead battery powered tools, plus a power supply built around the radio shack filament transformer Rotor included as his first post. The ones currently in use plug into a power bar (with circuit breaker) which, in turn, is plugged into the dedicated layout power circuit downstream of the, "Kill everything," switch.
Dedicated layout power circuit? That's what you get when you unplug the garage door opener and plug the trunk of the 120V layout power tree into the vacated socket.
Chuck (modeling Central Japan in September, 1964)
Lots of pople throw away old PC's, look for one and use it's power supply. You can even find new PC power supplies that are cheap, if you look hard enough.
There are lots of places on the Web with instructions on how to use them for non-computer purposes (since they're switching power supplies, you have to provide a load). Here's one example: http://web2.murraystate.edu/andy.batts/ps/POWERSUPPLY.HTM
HTH,Steve