One of the three long escalators at the Porter Square T stop is out of service. An apologetic sign on the work barricade specifies that work begins Jan. 7 and ends Jan. 11, a promise possible because the contractor, Kone, is performing maintenance, not repairs.

But this promise was merely poor prophecy. The escalator is still not working 10 days later, turning a tidy if leisurely five-day pause into a somewhat epic 15-days-and-counting freefall into paralysis.

Such work is done by at least two people, one out of sight in the bowels at the base of the escalator, one kneeling on the platform, peering into the blackness. Is this maintenance, done by choice, or repairs, necessitated by a breakdown? Maintenance, the watcher replies, seeming pretty harried for someone watching another person work. But it’s 10 days past the finish date. It’s taking longer than planned, she replies, a comment so unnecessary it approaches being meaningless.

The second worker pokes his head up, looking slightly more legitimately harried. Is this maintenance or repairs? Maintenance, the worker replies. But it’s 10 days past the finish date. The needed part didn’t arrive on time, he replies, leaving one to ponder an act of maintenance — a voluntary act to keep something in good working order — that is started, and cannot be completed, without a replacement part. It sounds very unlike maintenance at all.

But surely Kone knows what it’s doing. After all, it’s been fixing Porter Square’s escalators for a long time.

A very, very long time.