There is no Main ave. in Philadelphia nor has there ever been a Main Ave. There is Main St. in Manayunk but there isn't a 31 Main St. Main St. in Manayunk begins about 3700 North. At one time, both Germantown Ave. and Frankford Ave were called Main St., but again there wouldn't be an address of 31 for either of these streets. What is the source of your information? The street addresses haven't changed since 1930. There is a Maine Ave. in Upper Darby, Delaware County, a suburb of Philadelphia. Sndtenterprises Genealogical and Historical Research