Me again. I found some interesting info regarding train whistles and steps to creating quiet zones in North Portland. Check out these links for quiet zones, other states with train whistle/horn issues, and their resolutions

http://www.topix.com/forum/city/friona-tx/TVHP71DJG2RIISLIE/p2

http://www.railroadcontrols.com/qzs/

http://www.ipetitions.com/petition/train/

Here is a Portland Google group on Train Noise
http://groups.google.com/group/NPPCG?hl=en