From soon after its opening in 1930, there were 8 tracks, numbered from south to north 5-platform-6, 7-platform-8, 9-platform-10, 11-platform-12; this lasted until 3-platform-4 were added (in the 1970's?) in anticipation of a dedicated Airport Shuttle using those tracks. All were used, but outside of weekday rush hours more trains could be accommodated if needed. The usual am rush-hour operation would route 3 consecutive arrivals from any origins (all MP54's back in the day) to the same track; after all passengers had left, the 3 trainsets would close up to form one mammoth train (called a draft) which would then move out to Powelton Ave. coach yard. In the pm rush hour a super-long draft would move in to one of the 8 tracks and would then be split into 2 or 3 trains which were scheduled to leave one after the other for various destinations. There were automated display boards in the concourse, controlled from a central console; each had (if memory serves) 6 columns, each for a different destination (Wilmington, Media, Paoli, Norristown, Chestnut Hill, and Trenton, although I don't remember in what order). Each column showed the next 4 departures, with track number and location A or B. At the head of each stairway was a wooden display box into which were inserted metal signs showing the destination. There were always 2 openings, one above the other; the lower one was used for Chestnut Hill and Trenton trains having a connection at North Philadelphia with a train for the west and showed the name of the train it connected with. Off-peak there was a tendency to have certain tracks associated with particular destinations, so all tracks were used. I think Paoli usually got 11 and 12 -- at one time a number of destinations had 30-minute headways, and at one time Paoli and Bryn Mawr locals between them had a 15-minute headway off-peak.