As a former police officer turned locomotive engineer and now safety manager at Union Pacific, I've seen how a few seconds — and the right information—can save lives. One of the most important tools communities can use at a railroad crossing is the blue-and-white Emergency Notification System sign. It may look small, but it holds powerful potential.
http://www.up.com/aboutup/community/inside_track/ens-awareness-day-it-250624.htm