The "Train To The Plane" went down - again - Tuesday afternoon.
"Due to a power loss along the A line, bus shuttles are in place at all A line stations until further notice," the Regional Transportation District tweeted at about 3:20 p.m.
At 5:35 p.m. RTD stated that service had resumed between Union Station and the 40th/Airport station. Service fully resumed around 11 p.m.
The A Line, officially named the University of Colorado A Line, runs from Denver's Union Station to Denver International Airport.
A broken cable at the airport fell down and tripped a breaker, causing the power outage, RTD confirmed to Denver7.
Service on the A Line was also down briefly early Monday morning - also due to a power outage, RTD reported.
Bus shuttles were needed to transport riders between the 40th/Airport station and the airport on Tuesday, April 26. RTD did not say what caused that service disruption.
The commuter rail line between Denver's Union Station and the airport opened to the public on Friday, April 22.
There have also been delays along the A Line route due to malfunctioning crossing arms at intersections.
The Public Utilities Commission is requiring flaggers be stationed at each crossing around the clock, to help direct traffic in the event of a signal malfunction.
That requirement will remain in effect until the transportation agency’s new, first of its kind Positive Train Control system has been certified.
The commuter rail is designed to take passengers from downtown to the airport in 37 minutes, with six stops along the way. The line is 23 miles long. The fare is a flat rate of $9.