Fire alarm at South Station gummed up the evening rush hour.
Interesting thing happened at Attleboro as a result of it. Train 821 (4:30PM outbound) was delayed by half an hour, so train 823 (4:53PM outbound) was stuck behind it. This also delayed an Acela that normally passes 823 when stopped at track 3 at Attleboro, as well as the Amtrak Regional that leaves South Station just prior to 825 (5:40PM outbound).
821 dropped off passengers at Attleboro, slowly rolled out and then stopped at THACHER just ahead. 823 slowly crawled into the station to drop its passengers off. At this time, the Acela that was stuck behind the two got to pass, and the Regional was also behind got to pass as well, so both 821 and 823 were held at Track 3 in Attleboro just hundreds of feet from each other. During this time, there were four trains visible all going in one direction.
I'd imagine Track 3 from HOLDEN to THACHER is one signal block, right?
I was able to snag a picture of it, if you're interested.
https://i.imgur.com/g900NNG.jpg