Transport systems that begin each of the three theme answers

Question:

Answer:

SUBWAYS

Length:

Similar Crossword Questions:

Number of times this puzzle's theme word appears diagonally in the grid (to complete the puzzle, shade those words plus the Down answers that begin where they meet)
Brief time (found in all four theme answers)
Write in any of this puzzle's eight theme answers?
WORD OF CHEER HIDDEN IN THEME ANSWERS
Some film credits, and the idea behind the eight theme answers in this puzzle
Easy, and what this puzzle's theme answers literally are
How the other theme answers created this one?
Numerator for this puzzle's theme answers
Letters for the names "buried" in this puzzle's theme answers
Classic ad line, and question you need to answer to find the hidden theme in four starred answers
What this puzzle's theme answers start with
What one must have to solve this puzzle's theme answers
"Gosh!" (or, based on the starts of starred answers, one who is expert at solving this puzzle's theme?)
What you may be saying after reading the theme answers
Org. that has four teams with non-plural nicknames, which begin this puzzle's four longest answers
Word providing a hint to the hidden theme answers
Bit of footwear that appears at both ends of this puzzle's theme answers
___ to school . . . or a hint to the puzzle theme suggested by the ends of five answers
What the names in this puzzle's theme entries begin with
Secret the theme answers contain
Attendance check, and a hint to the puzzle theme in the first words of the starred answers
Shoe additions, and what this puzzle's theme answers contain
One way to describe the theme answers?
Time to feature any of the three theme answers?
Espresso order, or what each word pair in the theme answers synonymously represents