The PTA is expanding the stowage capacity of its Claisebrook Railcar Depot to allow the stowage of an additional 30 railcars at the eastern end of the yard. This has been brought about by the purchase of new "B-Series" railcars to be used on the Mandurah and Joondalup railway lines, the new stadium at Burswood, and the new Depot and Railcars associated with the Forrestfield Airport Link.

The stow yard will be used to stow rail cars for special events, additional services to run on the heritage lines, and other rail vehicles as required. A number of properties were built very close to the eastern end of Claisebrook Yard, and the PTA is seeking to lessen the impact by building a noise wall along the southern boundary. A retaining wall is also required to maximise the capacity of this part of the yard.