English Expression: Run out of steam
As we saw with the idiom, I introduced yesterday, a head of steam means to build up momentum and become successful. Well, today’s expression run out of steam is the opposite of that.
If you run out of steam, you lose momentum or enthusiasm for something, and you fail or give up.
We could say something like, after moving to Boston for university Hiroshi was enthusiastic about his new life, but his enthusiasm quickly ran out of steam, and he returned home before the end of the year.