Tens of thousands of commuters who use light-rail trains to travel through Pittsburgh ran late this morning.
The Port Authority of Allegheny County blamed an unspecified computer glitch that caused significant delays. At one point, trains couldn't travel into Downtown or the North Shore on Wednesday morning.
Transit spokesman Jim Ritchie said the problem was based in the rail operating center in the South Hills.
Trains returned to normal service about 8:15 a.m., Ritchie said, but they remained off-schedule through the morning rush.
It still isn't clear how the computer problems occurred, he said.