With the recent news that the Fremantle CAT will be withdrawn at the end of this month, here's a look at the history of this service:
The Fremantle CAT was introduced on 26 August 2000, replacing the Fremantle Clipper service and running in a figure-8 loop between James Street to the north and South Street to the south. The initial timetable was ambitious by the standards of the time: an 8-minute frequency at peak times (3pm to 10pm Thursday/Friday and 10am to 10pm weekends) and a 10-minute frequency otherwise (7am to 7pm Monday to Wednesday, and 7am to 3pm Thursday/Friday). This compared well to the former Clipper, which only provided a 15 minute daytime service on weekends and no service at all on weekdays.

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While the increased frequency was welcome, the evening services were generally underused and so an earlier finish time of 6:30pm was introduced throughout the week on the CAT's first birthday on 26 August 2001. Weekday morning services were also cut to start half an hour later.
The next major change occurred on 3 February 2002, when the route was extended south to Douro Road. In order to run the service with the same bus fleet, the frequency of the extended route was standardised to every 10 minutes at all times - however this still provided a high frequency weekend service in South Fremantle for the first time. It also compensated for the reduction in weekday frequencies from every 20 minutes on former routes 151 and 152 to every 30 minutes (and later every hour) on route 141.
The final extension to the CAT route was introduced on 14 December 2003, taking it to the Maritime Museum that had opened in Fremantle Harbour. The service then saw relatively few changes over the next few years, with the only noteworthy improvement being the reintroduction of a Friday evening service from 30 November 2007. This initially ran until 9pm, but was revised to an earlier 8pm finish from 8 March 2009.
2011 saw a major change to the Fremantle CAT service, with the original figure-8 design split into two separate loops to make the service more legible, accompanied by a reduction to a 15 minute frequency on the James Street route in an attempt to improve reliability. During the public consultation phase, these routes were referred to simply as the "North Loop" and "South Loop", however the final implementation saw the "Red CAT" and "Blue CAT" convention copied from the Perth CBD (all while the buses themselves retained their distinctive orange livery).
This form of the service operated nearly unchanged until the end of the decade, only picking up services on Boxing Day from 2016 onwards. However this wasn't to last, and from 16 August 2020 the Red CAT was "temporarily" suspended and the Blue CAT service frequency halved to an unpleasant 20 minute frequency in response to the Covid-19 pandemic - before the City of Fremantle puled their funding entirely three years later.