A program of Whole Foods Market , the mobile pop-up grocery will set up at the Rockwood Community Market in Gresham today from 3 p.m. to 6 p.m., and in Maywood Park in northeast Portland on Saturday from 10 a.m. to noon, bringing My Street Grocery to a five-day operation. The refurbished classic trolley car, named Molly, will also travel to Legacy Health in St. Helens , starting April 1 as part of a partnership with the local nonprofit health care system, expanding a food prescription program to a fourth location, the first rural site for My Street Grocery.