Multiple Regional Transportation District commuter rail lines will be impacted this weekend at Union Station as federally required testing is performed.

The A, B, G and N Lines will not operate to and from Union Station on Saturday and Sunday. Service will resume  Monday morning, according to RTD.

RTD said it will provide bus shuttles between impacted stations over the weekend. The shuttle will operate as such:

• A Line: Bus shuttle service between Union Station and the 38th and Blake Station.
• B and G Lines: Bus shuttle service between Union Station and 41st and Fox Station.
• N Line: Bus shuttle service will be offered between Union Station and the 48th and Brighton/National Western Center Station.

Officials said delays are anticipated because of the rail closures; riders are encouraged to explore alternative routes if their trip is impacted.