The transit agency says the full-length gates will stop people from jumping over them to avoid paying their fares.
Anyone trying to get out of paying would not be able to go over or under the gates.
An alarm would also go off if someone tried to run through after the person in front of them pays their fare.
SEPTA will install the first gates on the Market-Frankford Line at the 13th Street and 34th Street stations by early next year.