In N Out #3 Power Lines

Price range: $5.00 through $20.00

Solve this riddle:
“_____ hum above the _______ way,
Engines roar and ______ sway.
_______ crawl or rush along,
What flows in ______ both short and ____?”

Purchase The Print To Reveal The Missing Words

the answer is the 1st word in the collection riddle.  can you solve them all?