 And that's the 12th trip. So we would not have been able to expand beyond that without positive train controls. Now that we know positive train control is being installed, we can explore opportunities to add frequencies beyond the sixth round trip in the future. Positive train control is designed to automatically control train speed and prevent collisions and other accidents. Quinn says the system should be complete in about a year and a half. You're listening to Maine Public Radio. It's 435.