What is required to brake?

Siemens trains make up about a fifth of Metro’s fleet. They have had a history of problems with braking, which at various stages forced many to be suspended from service.> > > > > [Metro spokesperson Chris] Whitefield said last night’s incidents involved issues of “adhesion”, not braking.

via theage.com.au

What an awful example of PR spin. So blunt, so obvious. “Adhesion”? Really? How is that not a braking issue? In order to stop a moving train, the train is required to produce some friction with the ground, and not just slide around.