Twelve thousand people pass the north concourse every hour, and the old boards told all of them the same thing at the same time. The new wall reads the platform feed directly and gives each screen only the departures a traveller standing in front of it can still catch.
Reading the room
Depth sensors at the ceiling give an approximate crowd density, not identities — nothing is stored and no camera writes to disk. When a platform fills, the type steps up two sizes and the secondary information drops away.
The colour language is deliberately narrow: cyan for running, amber for held, magenta for cancelled. In eight months of operation nobody has asked what a colour means.
The brief was one sentence: make people look up once and know what to do.