im looking for an mrh advertiser who sells micro engineering ho weathered rail in code 83.  fast tracks sells non-weathered rail, but id like the weathered rail.  i have used me code 83 weathered rail flex track and that works well for me.  now, id like to try handlaying some track.  

Please may I ask for members expert advice on how I should wire my proposed fiddle yard correctly for DCC?

This will be my first DCC layout.  I have read and understand the principles and have seen and used DCC in operation, but this fiddle yard will involve reversing direction.  My plan for the non-scenic fiddle yard is below. I think I will need an auto reverse circuit and a power boost, but I am not really sure.

I know it's been posted here recently, but I can't find it with a bit of searching.  I'm looking for a web site which describes using a small transistor with one leg cut off (the base, I believe) as a constant current device for protecting an LED.  The page I saw showed photos of the LED and transistor connected to a 9V battery.

Because I need to use Code 125 Rail for certain pieces of equipment, the only option to have "girder rail" for O Scale is to use Code 125 Rail and adding code 100 rail perpendicular to the code 125 Rail.  This leaves for some interesting work to building traction line turnouts. I want to have only the single rail point (versus the traditional two rail points).