Can someone provide a brief overview or cite an article on the current car tracking system(s) on Class I railroads. I beleive that there is an AEI (?) tag on the cars and scanners along tracks. Is the tag electronic and does it communicate or is just read by the scanner? Are the scanners on all tracks, maillines, at entrances to yards, etc. Do the scanners use fiber optic networks along the reail or ar they wireless? Does this system work well? I read that the old GTE system from the '70s did not work well because the reflective material on the cars became too dirty for the scanners to work.
Thank you for your help.