Here are the correct answers for each blank:
- A track layer repairs a damaged train track. (Option e)
- A railyard engineer moves a particular engine to a different place to change cars. (Option a)
- A yardmaster tells other railyard workers to couple cars to an engine scheduled for departure. (Option c)
- A dispatcher instructs a locomotive engineer to change the train's speed. (Option b)
- A conductor tells a locomotive engineer to pull the train off the main track. (Option d)
So, the completed sentences would be:
- A track layer repairs a damaged train track.
- A railyard engineer moves a particular engine to a different place to change cars.
- A yardmaster tells other railyard workers to couple cars to an engine scheduled for departure.
- A dispatcher instructs a locomotive engineer to change the train's speed.
- A conductor tells a locomotive engineer to pull the train off the main track.