The Australind train service is set to recommence at the end of June.
The service was suspended in November 2023 during the Armadale Line upgrade and has taken over two years to resume.
Four new trains will be introduced in stages, with the first train entering service on June 29 and the remaining three to follow over the coming months.
Some coach services will operate until the second train comes online.
The three-car trains replace the older fleet which started services in 1987.
The new Australind trains feature LED lighting, in-seat USB-C charging, improved accessibility, an onboard buffet and dedicated storage for 14 bicycles per train.
Each of the new Australind trains will also feature unique Aboriginal artwork by a local Indigenous artist.
"I'm so excited for the return of the Australind, with new trains and more frequent services for local communities from Byford to Bunbury," Transport Minister Rita Saffioti said.
"We thank the community for their patience during the important testing and commissioning phase of the four new Australind trains.
"This work has been essential to ensure the fleet meets the highest standards of safety, reliability and performance before welcoming passengers on board.
"These new trains will not only provide a more comfortable travel experience for locals and visitors, but we'll be increasing the frequency of this service supported by a $45 million investment in our upcoming State Budget."
The Australind's stopping pattern will remain unchanged, with services operating on the original route between Perth and Bunbury, stopping at Armadale, Byford, Mundijong, Serpentine, North Dandalup, Pinjarra, Waroona, Yarloop, Cookernup, Harvey and Brunswick Junction.
A community event to celebrate the return of the service will be held at Bunbury Passenger Terminal on Sunday, June 28.
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