I just got a great phone call from Matt O'Malley's office. I emailed them last week after the first 3 days of track work in JP and the annoying horns that seemed to be blasting all day and all night in the Stony Brook area. (Happily, it's quieted down a lot since then.) They did a great job of following up.
Valerie from that office has been in touch with Amtrak. Amtrak confirmed that federal safety regulations require only that trains blow their horns once when they enter a work zone and once when they leave. There is no need for the long or repeated blasts throughout the work zone that we've been hearing at times. That's just the operator having a little too much fun. She said if it gets bad again to let them know.
Just wanted to let people know about the good response from that corner and what to do if it starts getting needlessly loud again this summer.