Walking Boston snapped one of the Green Line's new next-train signs, which shows, well, the next train to arrive, but, unlike the signs on the other lines, not when it's due.

"For the first time in the 100-year history of the Green Line, customers on the outbound platform will no longer have to guess which train is coming next," state Transportation Secretary Richard Davey said.

Providing arrival time information will take additional technology to track Green Line trolleys; the T hopes to release a schedule for installation of that sometime in the next few months.