I'm not seeing much on the MBTA site, but word on the train was that it was signal issues. I would be surprised if it was related to Foxboro, but there were a lot of people unhappy about the changing schedule on top of the delays. My biggest concern would be this leaving a sour taste in people's mouths, but if literally anything goes wrong on that line the comments on the MBTA Rail app start professing damnation upon entire countries, so I don't think it's a major issue.T Alerts would have the location. Most likely a mainline or NEC delay, as there's only 5 miles total of track between Walpole Jct. and Foxboro Station. Odds favor the usual culprits overwhelmingly over the new route.