Expect delays between 45 to 60 minutes if you plan to take the A Line between Union Station and Denver International Airport this weekend.

That’s according to a bulletin distributed by RTD on Tuesday afternoon.

RTD says the delays stem from work on the forthcoming N Line, which will serve the north metro area. For part of the weekend, a contractor will need to power down a portion of the commuter rail system – so, in spots, the A Line will be replaced by a bus shuttle.

Expect the disruption between 3 a.m. Saturday and 3 a.m. Monday, according to RTD. It’s the second of four planned disruptions slated for the coming months.

During this time frame, there will be no rail service on the A Line from Union Station to Central Park.

Instead, there will be bus shuttles every 15 minutes from 4:15 a.m. and 6:30 p.m., and every 30 minutes outside that timeframe.

There will be regular service at the other stations, RTD said.