The mayor responded by ticking off the first three of the eight stages outlined by the activists.
The move came just hours ahead of West Yorkshire Combined Authority's annual general meeting.
The AGM marks a year since the mayor initiated the legal process needed to make a decision on bringing buses into public control.
Ms Brabin’s flagship policy in her 2021 election was “to bring buses back under public control” so that they “start putting people before profit”.
After Freedom of Information Requests showed that no progress had been made in the mayor’s first six months in office, the Better Buses for West Yorkshire campaign, Unite Community, and the Yorkshire TUC now believe there has been movement.
The most recent report to the WYCA Transport Committee showed that the first three key steps of the public control process, which consists of eight stages, are now progressing.
The steps ticked off by Ms Brabin included: developing the compelling case for change, setting objectives, and options generation and refinement.
Mick Fitzpatrick, a member of Unite Community, from Batley, said: “As a bus user throughout my life I have never known a worse time.
“Having never owned a car I have spent my time cycling, walking and using public transport. Now in my seventies, I am increasingly dependent on the buses.
“Cancellations, a restricted bus service especially at night and evenings mean that despite living in Batley between the major towns of Halifax, Bradford, Leeds, Wakefield and Huddersfield I am unable to get home at all much later than 11pm.
“Private companies have been treating buses in Batley as cash cows for years, paying out tens of millions in dividends in the last decade.
“This progress towards a decision on bringing buses into public control gives me peace of mind that better buses, with communities like mine prioritised over the interests of overseas shareholders, are just around the corner.”