A: Can you take charge of the half-year financial report?

    B: Sorry, I can’t. I’ve been working 15-hour days for two weeks straight. I think I’ve run out of steam for a while. I need a break.

    Note: This idiom means to “be completely out of energy.” Coal powered trains run on steam. The allusion in this phrase is clearly to steam engines which gradually slow and then stop when the fire that powers the boiler is too low to produce steam. The first figurative uses come from the United States in the late 19th century. It’s used commonly to state that someone has become exhausted and can no longer continue working. People also use a similar idiom “running out of gas.”