Of course rape happens. It has always happened in women’s prisons even before transgender prisoners were put in there. Transgender individuals who are biologically male should be in a separate wing/ward, they shouldn’t mix with female prisoners. But the idea that womens prisons used to be rape free is incorrect. Of course it’s not “legally” rape when it’s female on female rape, but given the objects used and the damage caused can exceed that of a penis, it is a type of rape imho.