The Amtrak passenger trains seem to have a higher speed limit than freight trains do. I've noticed that difference at the Brighton Ave crossing near Punky's. It seems likely they'd have about the same speed since those crossings aren't that far from each other and have similar curves nearby. Maybe 20-25 MPH vs 10-15.

Downeaster service isn't that new, but if someone has a lifetime habit of cutting in front of freight trains they'll be in real trouble trying to beat the passenger ones.