Less than four years after a California train disaster spurred passage of major safety legislation, railroad companies are pushing hard to relax the law’s chief provision. They have won over key Republicans, and extracted a major concession from the Obama administration, in their bid to scale back and delay a system to prevent crashes such as the head-on collision that caused 25 deaths and 135 injuries in Chatsworth, Calif. The Rail Safety Improvement Act, passed in late 2008 soon after the Chatsworth disaster, mandated the $13 billion project and stuck railroad companies with nearly all of the cost. The law calls for installation of a technology known as Positive Train Control, or PTC, that automatically puts the brakes on trains about to collide or derail. http://openchannel.msnbc.msn.com/_n...ght-safety-rules-with-help-from-gop-and-obama So why would it cost so much, 13 billion, to come up with a way to just prevent the trains from colliding with each other? If a signal was being transmitted that could be recieved up to 5 miles away that lets other trains, on the same track only and heading towards them, that they should automatically start stopping and sound an alert.