Philadelphia crash shines unforgiving light on US signalling effort

New system faces morass of regulatory, technical and financial delays
Rescuers work around derailed carriages of an Amtrak train in Philadelphia, Pennsylvania, on May 13, 2015. Rescuers on May 13 combed through the mangled wreckage of a derailed train in Philadelphia after an accident that left at least six dead, as the difficult search for possible survivors continued. AFP PHOTO/JEWEL SAMADJEWEL SAMAD/AFP/Getty Images

When the driver of a Los Angeles commuter train jumped a red signal and ploughed into an oncoming freight train in September 2008 while sending a text message, the political reaction was swift.