Commuters on the Armadale, Thornlie and Midland lines will be forced to use shuttle buses while two stations close for work on the Perth City Link project this weekend.
Perth and McIver will close and commuters on the three lines will have to take shuttle buses from Claisebrook Station to the city.
Shuttle buses will also run between Thornlie and Cannington stations.
The closure will start at 8pm and run until Sunday night.
Fremantle trains will be diverted to Perth Underground station over the weekend and may be delayed.
Transperth had advised commuters to allow extra travel time during the weekend and remember surfboards and bicycles were not permitted on buses, including the replacement buses.
The Mandurah and Joondalup lines are not affected by the closures.
Normal services will be running on Monday morning.
Workers on the Perth City Link project this weekend will focus on the Northbridge end of the Eastern Concourse, which runs between Forrest Chase and the cultural centre.
The Eastern Concourse will remain open throughout the weekend for pedestrian through-traffic.