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)
Athletic boost "taken" by the four theme answers
Rebelliously, perhaps (and a hint to this puzzle's four theme answers)
Reverend whose name is linked to terms like "Pazz and Jop," and this puzzle's theme answers
It may be involved in tallying the four theme answers
What this puzzle's theme answers start with
Postseason gridiron game, and a hint to the puzzle theme found in starred answers
Like the theme answers in this puzzle?
WORD OF CHEER HIDDEN IN THEME ANSWERS
Some film credits, and the idea behind the eight theme answers in this puzzle
Brief time (found in all four theme answers)
Write in any of this puzzle's eight theme answers?
What each completed pair of theme answers in this puzzle is
"Home work" letters that appear at both ends of this puzzle's theme answers
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
"Gosh!" (or, based on the starts of starred answers, one who is expert at solving this puzzle's theme?)
What one must have to solve this puzzle's theme answers
Any of five that begin this puzzle's longest answers
Like the three marriages described in the theme answers
What you may be saying after reading the theme answers
Number inaugurated into this puzzle's theme answers
Shade from the sun that's inserted in this puzzle's theme answers
Word providing a hint to the hidden theme answers