Fellow blogger Miles recently did a very comprehensive review of Worcester's Union Station. He has a growing collection of MBTA station reviews, including a few of the Framingham-Worcester line stations. I've added a section to my "Helpful Information" page with links to all of his Framingham-Worcester line station reviews. Check it out, especially if you've never been to any of the stations. Interesting stuff!
Not an MBTA employee, not a Keolis employee, just a regular commuter (with a scanner and some knowledge of railroad operations). Everything here is my speculation, so up to you to judge the accuracy.