government accountability office, robert bourg, strategic development, wabtec corporation. chris matthews, assistant vice president, network control systems, bnsf of railway, and jim derwinski, chief executive officer and executive director of metro. today's hearing will evaluate progress in implementation positive train control, ptc, and examine potential challenges in meeting the final implementation deadline of december 31, 2020. as recent committee hearings have highlighted, ptc is an important technology that has the ability to prevent accidents, including over-speed derailments, such as the tragic derailment in dupont, washington in 2017, as well as preventing train-to-train collisions. ptc enforcement and implementation act, passed by congress and signed into law by president obama in october 2015, required railroads to implement ptc by december 31, 2018, however it allowed a railroad to apply for an extension of up to 24 months if, and only if, a railroad met important milestones. i am pleased to say that under secretary chao and administrator batory's leadership, t