Shuttle buses will replace part of Metra’s Rock Island District service from the south suburbs Saturday night to Sunday morning to allow for track replacement work at a junction south of the Loop.

Passengers on the last inbound train Saturday night, which is scheduled to arrived at LaSalle Street Station at 11:45 p.m., and the last outbound train, which departs LaSalle at 12:30 a.m. Sunday, will be bused between LaSalle and the 35th Street/Lou Jones station, according to Metra.

The service change is required for track work south of the Loop, Metra said. Canadian National Railway crews will replace tracks at the junction where CN tracks cross Metra’s tracks, just south of Metra’s 16th Street Tower.

Four sections of track, known as “diamonds,” will be replaced from Saturday night to Sunday morning, and Metra workers will replace the drainage underneath the tracks, Metra said.

The work is scheduled for overnight hours “to minimize disruption to passenger service.”