Train and ferry replacement bus services are numbered in the 900s, and operate when those services are interrupted. When only part of a train line is closed, the replacement buses will operate between the nearest open stations. As of October 2016, buses replacing Perth Station services depart from Perth Busport; previously, they departed from Roe Street bus station. Private operators such as Buswest may be used if there are insufficient Transperth-branded buses available, such as when unscheduled disruptions occur during peak periods.