SEPTA Boarding Announcements

Have you ever wondered who makes those SEPTA boarding announcements in the Market East / Gallery station? You know the deep voice that says "The next train to arrive will be the 4:40 R2" and things like that? I saw the secret today. A woman in SEPTA uniform was standing at one of the conductor's stations on the platform. She had opened a panel on the wall in front of her. The screen inside had three columns. One was a list of expected trains, one said arrival, the other said boarding. She used a stylus to select the incoming train and whether it was arriving or boarding. Within seconds the announcement came over the intercom. As each train boarded it scrolled off the top of the screen. Just one more of life's little mysteries explained.