Some parts of the center platform will have a glass wall, some parts (stairwells and storage rooms) have cement support walls along the platform which have been painted white. I too am hoping they plan on backlighting but before the glass went up I didn't notice lights in the gap between the glass and the white wall.
There was a discussion on this a bit up this thread.I don't know if its been answered before, but after boarding the subway at Union on the new platform, I couldn't help but notice that the low ceiling leaves no room for digital signage.
Is there a plan to add screens to the station somewhere displaying next train, and service advisorys at the platform level?
If you were an artist this would be a pretty cool commission to win. You basically have a captive audience of hundreds of thousands of people every day forced to stand and stare at your work whether they want to or not. "Look at my art! Look at it!"