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)
"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
Bit of footwear that appears at both ends of this puzzle's theme answers
Characters who "haunt" this puzzle's theme answers
Each of the titles in this puzzle's theme answers, e.g.
Shoe additions, and what this puzzle's theme answers contain
What the names in this puzzle's theme entries begin with
Easy, and what this puzzle's theme answers literally are
Secret the theme answers contain
Attendance check, and a hint to the puzzle theme in the first words of the starred answers
Time to feature any of the three theme answers?
One way to describe the theme answers?
Announcement/event of September 2011, or what happened to the theme answers
Org. that has four teams with non-plural nicknames, which begin this puzzle's four longest answers
Espresso order, or what each word pair in the theme answers synonymously represents
___ to school . . . or a hint to the puzzle theme suggested by the ends of five answers
Supplements added to each of this puzzle's theme answers
One who can be patched together from the letters added to the theme answers