Yes, that’s a QR code on the Revolution’s side-trolley ad.
Snapped this at the Arlington station last night, where my radio and digital signal on my phone were squarely at “zero”. So, it would have been really not useful if I used that magical app on my phone to scan the code and land at whatever webpage they were advertising.
Then again, maybe I shouldn’t knock it. Maybe this is a new investment by MBTA in culture. Perhaps this is a performance art installation of a QR code, seeing if people will run after that train as it flies down the B-line tracks on Comm Ave, working to scan it. If that is the case, then BRAVO, MBTA. Bravo.