The A Line continues to employ crossing guards because of a history of gate malfunctions.

Much ink has been spilled over problems plaguing the Regional Transportation District's A Line — the Train to the Plane — since it opened in April 2016.

There have been crossing-gate malfunctions and delays, and on April 20 of this year, trains lost power between the DIA and 61st/Peña stations, stranding some passengers without food, water or bathrooms for more than three hours. At an RTD board of directors meeting on May 15, RTD District Director Chuck Sisk called the incident “unacceptable” and told the private contractor that runs the A Line, Denver Transit Partners, "This cannot happen again.”

So how often is the A Line delayed?

From April through December 2016, A Line trains were 87 percent reliable. That number jumped to 90.4 percent from January to April 2017.

During its second year of operation, from May 1, 2017, through April 30, 2018, the on-time performance percentage of the A Line was 96.2 percent.

That's with more passengers, too: RTD reported an 86 percent jump in ridership during the first three months of 2018 (1.56 million passengers) compared to the first three months of 2017 (876,000 passengers).

So there you have it. Despite complaints and occasional incidents, the reliability of the A Line has increased considerably. Assuming that number holds steady, there's a less than 4 percent chance that trains going to or from the airport will be delayed.

Still, riders should always build in extra time when going to the airport — just in case.