plug away vs keep one's shoulder to the wheel

plug away and keep one's shoulder to the wheel both are verbs.

Word	Noun	Adjective	Verb	Adverb
plug away	No	No	Yes	No
keep one's shoulder to the wheel	No	No	Yes	No

As verbs, plug away and keep one's shoulder to the wheel are synonyms defined as:

plug away and keep one's shoulder to the wheel: work doggedly or persistently

Other synonyms of plug away include keep one's nose to the grindstone, peg away, slog.

plug away (verb)	keep one's shoulder to the wheel (verb)
persist in working hard	work doggedly or persistently
work doggedly or persistently