Bottom Line
Kevin Wald
The solver must select sequences of boxes, from top to bottom, that form clues; when this is done, some of the clues are incomplete. In order from left to right of the top boxes (and thus also of the answer boxes), we have:
WHAT CELLS ARE/SAID TO DO EVEN/IF IN FACT/THEY PLAY SONGS: RING
MR ESCO/BAR OR MR/GONZALEZ/PLAYING IN/ . . .
LAST WORD OF/COMIC BOOK/GUY'S SIGNATURE/LINE: EVER
TRIGRAM WITH/WHICH A/BUSINESS DO/MAIN NAME ENDS: COM
IN ZEN AN/ANSWER/THAT UNASKS/A QUESTION: MU
NUMBER/OF PLAN/ETS SMALLER/THAN LA/ . . .
NOMINATIVE/PRONOUN FOR/UN GAR/CON: IL
EMU/LATE ING/MAR/BERGMAN: DIRECT
ATOMS WITH EXTRA/OR MISSING/ELECT/RONS: IONS
COMPANY WHOSE/PRODUCT BROKE/THE SALES/RECORD/ . . .
PART OF A/WEDDING GOWN/THAT MIGHT GET/TRODDEN ON: TRAIN
SCOTT/FITZGERALD/OR LEE/BAILEY: F
TOON/WHO IS/OF MEXICAN/ORIGIN/AND CAN/ . . .
TWO NINTHS/OF A KELVIN/WARMER THAN/-18C: 0F
WHAT SOME/S IS IN A/PREMISE OF/FAKOFO: NOT M
GOLD WHEN/USED AS A/HERALDIC/TINCTURE: OR
FIRST NAME OF/THE HUNT'S/HOST TWO/YEARS AGO: ETHAN
Each of these groups of answers, when the blank left by the incomplete clue is filled in appropriately, forms part or all of the bottom line or two on a posted sign in a car on the Red Line of the T:
RING [THEN L]EVER
COMMU[TER RA]IL
DIRECTIONS [OF THE] TRAIN
F[INE] OF NOT MORE THAN
When these blanks are filled in, three of the clues are now complete (and can have their answers put in the next row of boxes) and one is still incomplete:
MR ESCO/BAR OR MR/GONZALEZ/PLAYING IN/THE NL: ALEX
NUMBER/OF PLAN/ETS SMALLER/THAN LA/TERRA: TRE
COMPANY WHOSE/PRODUCT BROKE/THE SALES/RECORD/OF THE/ . . .
TOON/WHO IS/OF MEXICAN/ORIGIN/AND CAN/INE: REN
This again forms part or all (depending on what car you are on) of the bottom line on a posted sign on a Red Line car:
AL EXTRE[MO DEL T]REN
So the last clue, completed is:
COMPANY WHOSE/PRODUCT BROKE/THE SALES/RECORD/OF THE/MODEL T
And the answer is VOLKSWAGEN (the Volkswagen Beetle was the first car to outsell the Model T Ford).