The MBTA now has its first "countdown" signs at an underground Green Line station, to tell riders when the next trolley is set to arrive.
T General Manager Frank DePaola and Administrator Brian Shortsleeve unveiled the new digital monitors at Kenmore station Thursday morning.
The signs display the number of minutes until the next B, C or D trolleys arrive at the station.
DePaola hopes the monitors will be useful, especially for people packing the station after a Red Sox game.
"A lot of people have experienced listening to the steel wheels and running through the gates and down the stairs to catch that Green Line train, just to find out that it happens to be not the letter they're looking for," he said.
More countdown clocks will be activated in other underground Green Line stations in the coming weeks and months; the signs at Hynes station will be activated next week, the MBTA said in a statement.
The Green Line has America's oldest subway tunnel, at 118 years old.
This article was originally published on August 13, 2015.