What is a train-related expression for exhaustion?
Options:
- have rest
- run out of steam
- go to sleep
- tuckered out
- stay in bed
Let's think carefully first. Step-by-step reasoning process:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
A train-related expression for exhaustion is to run out of steam. So the final answer is run out of steam.