The need for a visiting judge arose after the Montgomery County bench recused itself from the trial for Kerns, 67, of North Wales, a longtime political figure.
Montgomery County prosecutors charged him in late 2013, weeks after they said he raped the woman, an employee of his former law firm, following an office party. County authorities withdrew those charges after acknowledging investigators had misread lab results, but the state Attorney General's Office refiled rape and other charges.
Last month, a district judge dismissed the rape and sexual-assault charges and ordered Kerns to trial in Common Pleas Court on other counts, including a felony charge of aggravated indecent assault.
Braxton, who will preside at that trial, is no stranger to handling cases against politically prominent defendants. A longtime Philadelphian, he was called to Chester County for the 2013 trial of former District Judge Rita Arnold, convicted of concealing a citation against her son.
On Wednesday, Braxtton could not be reached for comment.