This is for Jerry, who asked how I did the bridge lighting. Although he wasn't the first.
What follows is a series of pix I took while building the Atlas Bridge. Luckily, I thought to take some shots at the time.
The lights are three warm-white LEDs, wired in series with a 560 ohm resistor on the negative end. Could be a 680 ohm... I forget. :D I run all my LED lighting to a bus run by a 9V power supply, leftover from God knows what...
The lampshades are plastic wheels with a 1/8" hole drilled in the middle. The original axle hole is just a bit too small.
The wires are strung through the backside of the bridge and run behind an abutment, then through the subroadbed to the bus.
Did some bridges have lighting? Yes, but probably didn't look like my finished product. I'm into the details on my rolling stock, but anything goes with scenery.
Regards,
Jonathan
(http://i642.photobucket.com/albums/uu146/jsnvogel/Projects/DSCN1053_zps6829edf0.jpg)
(http://i642.photobucket.com/albums/uu146/jsnvogel/Projects/DSCN1059_zps6c15985f.jpg)
(http://i642.photobucket.com/albums/uu146/jsnvogel/Projects/DSCN1060_zpse399e49d.jpg)
(http://i642.photobucket.com/albums/uu146/jsnvogel/Projects/DSCN1061_zps07f35329.jpg)
(http://i642.photobucket.com/albums/uu146/jsnvogel/Projects/DSCN1062_zps7275e6aa.jpg)
(http://i642.photobucket.com/albums/uu146/jsnvogel/Projects/DSCN1063_zps2f68d373.jpg)
(http://i642.photobucket.com/albums/uu146/jsnvogel/Projects/DSCN1064_zpsb2894639.jpg)
(http://i642.photobucket.com/albums/uu146/jsnvogel/Projects/DSCN1070_zps52c38e4c.jpg)
(http://i642.photobucket.com/albums/uu146/jsnvogel/Projects/DSCN1077_zps4445baaa.jpg)
You may find the following guide from the US Coast Guard useful. I found it while looking for marker light information for my Bascule bridge.
http://www.uscg.mil/hq/cg5/cg551/Lighting.pdf
A popular alternative is to use stranded motor/magnet wire. These can easily handle the 20ma that the lamps require and are considerable thinner then standard wires to help keep them hidden. You just need to sand the end to remove the insulation.
http://www.walthers.com/exec/productinfo/514-N5038
Thanks jonathan and thanks to digital I like the link you provided as I can not recall ever seeing lights under the bridge on a layout. Adds a nice touch.
Jerry
Jonathan: Thanks for the pictures and descriptions of the installation.