Alert readers Michal Bryc and Dick Burkhardt have gotten responses from Sound Transit on when we can expect to have next train announcements at Link stations:
Due to the work being done in the Airport Station the train arrival message will not be activated until the end of November. We have been working on integrating this station into the Central Link system and it requires us to use two different train tracking approach one for the Central Link and different one for expanding to the Airport. As we are so close to opening the Airport Station we decided to hold off on implementing arrival messages for Central Link until we can include Airport Station and its new schedule, and to facilitate our testing of Airport Station.
So there you go.