A interesting thing, when I drive MBTA Providence #806, I was delayed about 10 mins, the signal was red when I approach the Ruggles station. And when I contact the signaller it allows me to pass, the ATC/ACSES also changed from 0 to 30. When I get into the station, the PIS shows I am the next 4th train. When I left that station everything backs to normal and I was showing as the first train when I arrived at Boston Back Bay.
