Finally, those LED signs at many MBTA stations will start providing useful information beyond the date and time. Last week at South Station, the transit agency began displaying how many minutes before the next train arrives. Other stations on the Red, Blue, and Orange lines could be similarly equipped by the end of the year. The T should move as swiftly as possible: While customers of other subway systems around the world have long taken such countdowns for granted, this is a clear improvement for the T.

Now the agency should find a way to generate real-time data for the Green Line — whose tracks lie in large part above ground, and whose riders are likely to be waiting out in the rain. The successful effort to generate data for the other three lines provides a blueprint. For many years, T officials maintained that the aged system couldn’t provide such information on those lines, either. But to its enduring credit, the agency decided to release real-time data generated when trains trip signaling systems, and software developers quickly stepped in to develop smartphone apps that satisfied customers’ most basic questions: How much longer will I be waiting on this platform? And when I get to Downtown Crossing, is it worth rushing to make the next train?

If seeking ways to give Green Line patrons access to the countdown data that Red, Blue, and Orange Line customers will soon be receiving, the T should lean harder on the same outside brainpower that developed the smartphone apps.