Yesterday, Association of American Railroads (AAR) President and Chief Executive Officer Ed Hamberger told a Senate committee panel that U.S. freight railroads have determined that it will be impossible to launch a fully interoperable nationwide PTC system by the mandated year-end 2015 deadline."A lot of progress toward implementing PTC has been made to date and railroads are working extremely hard to meet the 2015 deadline, collaborating with federal regulators and suppliers all throughout the process," Hamberger said. "There will be a lot of PTC implemented throughout the nation's rail network by 2015, but there will not be a fully interoperable system in place by then. While the deadline is important and something we never lose sight of, it is paramount that we end up with a PTC system that allows for the safe passage of both passengers and freight."Last month, several passenger-rail executives told me that several challenges are making it tough for their agencies to meet the PTC deadline. Still, they're plowing ahead to get as much done as possible. You can read more of their PTC concerns and progress in my article published in this month's issue of Progressive Railroading.And to read more of Hamberger's testimony, follow this link to ProgressiveRailroading.com.