A power failure stopped the A-line to Denver International Airport Monday morning.
RTD-Denver tweeted at 4:41 a.m. that the A-line was down.
Power was restored about 30 minutes later.
RTD-Denver tweeted that passengers should expect delays as service was restored.
There's no word yet what caused the power failure.
The University of Colorado A-line started operations April 22.
In addition to power problems on the line, RTD was ordered to staff each crossing around the clock , to help direct traffic in the event of a signal malfunction.