An RTD FasTracks train at Union Station, Denver, April 11, 2016.

(Hart Van Denburg/CPR News)

Repeated shutdowns and delays in service on the commuter rail line between downtown Denver and the airport has resulted in city transportation officials withholding more than $800,000 from the company that operates the route.

The Denver Post reports Regional Transportation District spokesman Scott Reed says the deductions are based on Denver Transit Partners' performance. The performance stipulations are part of the 34-year contract RTD has with the company for operation and maintenance of the University of ColoradoA-Line.

Since opening in April, the $1.2 billion line has experienced a series of outages and problems with crossing gates.

Denver Transit Partners says it's "committed to providing safe and reliable service" for customers on the 23-mile line.

RTD pays the company around $3 million each month to operate the rail service.