All passenger services on the Armadale and Thornlie train lines will be cancelled this weekend, while Mandurah passengers will also face disruptions this month.
The last service will run from Armadale at 6.47pm Friday, and from Thornlie 18 minutes later, to allow an upgrade of Oats Street station.
Buses will be used in place of trains to run replacement services.
Services will return to schedule on Monday morning.
There will also be no trains running between Mandurah and Rockingham for the four weekends from January 16, to allow tunnel construction on the Mandurah Entrance Road project.