In practice, the term Engineer is used loosely. The term P.E. never loosely.
Before there were all your beloved modern engineers, there were the military men who destroyed castles and other fortifications and therefore were hired to make them less destroyable. Thus the Army Corps of Engineers today.
When steam engines were developed, they required constant care, lubrication, adjustment and repair by engineers. And when steam was put on rails, the people who ran the engines logically became engineers.
So who stole the respectable titles - at least chronologically?
This is a pet peeve of mine, too. It must have come from the notion that people who drove trains drove the engines, and were therefore engineers.
Don't forget Operating Engineers (mainly cranes and material handling machinery) and Stationary Engineers (mainly pumps and generators). Also don't forget sanitary engineers. One is a job description and one is a professional occupational title.
An American aberration. No civilised person does it.
I just feel like that takes away from the career title engineer (pertaining to civil engineers, chemical engineers, biomedical engineers, etc.). I'm not saying being a train driver isn't a respectable job, but to become one there's no higher education or continuing ed requirements, as opposed to real engineers who need to go through rigor to attain their degrees.
Sorry if I offend or bore anyone with this lol...this is just a huge pet peeve of mine.