Josh Funk, AP Business Writer

Air traffic controllers in Denver had to scramble to use backup frequencies after their main communications lines went down for 90 seconds earlier this week in the latest Federal Aviation Administration equipment failure. The FAA's head of air traffic control, Frank McIntosh, said during a House hearing Thursday that the outage in Denver happened Monday afternoon but its radar remained online.

Union Pacific will renew its push for one-person train crews later this summer when the railroad tests out the idea of having a conductor in a truck respond to problems on trains in Nebraska and Colorado. Union Pacific will continue using two crew members on its trains during the test, but railroad officials believe this could bolster their case in future negotiations for cutting crew size if it is successful. A UP executive confirmed the plan Monday when he testified against a proposed Kansas rule that would require two-person crews. All the rail unions have long opposed cutting train crews down to one because of safety concerns, but the conductors' union agreed to let Union Pacific test this idea.