The Regional Transportation District is kicking off a monthlong maintenance project Sunday, resulting in periodic closures of the N Line through next month.

Crews will resurface the commuter rail track along the N Line from Union Station in downtown Denver to 124th Station in Thornton, according to the transportation system. The work is scheduled to conclude in mid-December.

The first segment of work will start south of Thornton Crossroads-104th Station and go north toward Northglenn-112th Station, according to the system. The work will take place from 10 p.m. to 4 a.m. nightly through Nov. 23.

The work is not expected to take more than two days in each location. The bulk of the work is planned to take place outside of service hours or when customers are not present, according to the system.

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“RTD knows that people notice the quality of their train ride,” the system said in a statement. “Running multiple trains across the lines throughout the service day inevitably leads to shifting and settling of the ballast, the rocks under the rail, beneath the tracks.”

The resurfacing process corrects rail alignment for a smoother ride, picking up the rail and rail ties, then pushing metal paddles into the ballast to vibrate and compact the ballast under the ties, according to the system. This gets rid of dips in the rail.