For public transport to the hotel, the link below has general background information on SEPTA's Regional Rail Line that runs from the airport to center city every 30 minutes:
https://www.phl.org/getting-around/public-transportation
Attendees should take the train to Jefferson Station which is just across the street from the Marriott. Exit Jefferson station following signs for 12th St. The Marriot address is 12th and Market but the entrance is at 12th and Filbert.
https://wwww.septa.org/accessibility/