It wasn't on the public list of engines acquired by Atlas, so I would assume they still have it provided Lionel didn't purchase it (which I find highly unlikely considering Lionel already has an even higher-detailed model, themselves).
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .