The Engineers Thumb What type of engines did the engineer in story specialize in?

The story "The Engineer's Thumb" by Edgar Allan Poe doesn't actually specify the type of engines the engineer specialized in.

The story focuses on the engineer's mysterious disappearance and the gruesome discovery of his thumb, leaving the details of his profession rather vague.

While the story is set in a time when steam engines were prevalent, there's no concrete mention of the engineer's particular area of expertise within that field.