More than 30 Freedom Riders travelled to York on Monday to demonstrate outside a British Transport Police disciplinary hearing.
One of the BTP officers responsible for the violent arrests of two protesters at Sheffield station three years ago is facing charges of gross misconduct.
The Freedom Riders were joined by dozens of members of the National Pensioners Convention and other supporters.
The chanting outside could clearly be heard in the hearing.
The group later went into the city centre to distribute leaflets, getting a great response from passersby.
The hearing was expected to last all week.