The National Transportation Safety Board (NTSB) yesterday urged the Federal Railroad Administration to evaluate safety requirements imposed by the Canadian government on lone-engineer operations and to implement any of them that might be useful for U.S. railroads that use such operations on track that lack anti-collision technology. The recommendation is included in the NTSB's final report of a collision between an Amtrak passenger train and a freight train nine months ago that injured more than 60 people. The NTSB determined the probable cause of the accident to be the Amtrak engineer's inattention to the operation of the train, which led to his failure to recognize and comply with the speed limit imposed by the governing wayside signal, and the lack of any safety redundancy system capable of preventing a collision in the event of human failure. Although Amtrak has had lone-engineer operations for decades, the NTSB said that it is concerned that such operations without the protections of positive train control (PTC) provide no protection against human error. With a PTC, a train would come to a stop if the engineer failed to properly operate the train in conformance with signal indications.