quiet car
n. A train or subway car where riders cannot have cellphone conversations or use noisy devices.
Other Forms
Examples
2011
Beginning Oct. 3, a passenger car on every weekday Metrolink train will be designated as a "quiet car." Cellphones, smartphones or electronic devices that can be heard by others will not be allowed.

"Some of our passengers prefer to socialize or do business on the train. We encourage that — just not on the new quiet cars," said Metrolink Board Chairman Richard Katz.
—Alejandra Molina, “No cellphones on Metrolink's quiet car,” Orange County Register, September 28, 2011
2011
The Long Island Rail Road plans to test a "quiet car" on some trains this fall, giving customers a tranquil refuge from annoying ring tones, loud cellphone conversations and assorted other auditory nuisances….

For years, commuters have called for the LIRR to take action against obnoxious chatterboxes. Railroad officials previously said it would be difficult to enforce a quiet-car policy.
—Alfonso A. Castillo, “LIRR plans to test 'quiet cars',” Newsday, September 23, 2011
1997 (earliest)
Many people go to cars at the end to have a ''civilized ride,'' but that strategy is shaky now, according to Dodson. ''It's difficult when you're surrounded by yuppies yakking away on their cell phones…"

The Commuter, whose cell phone never seems to work on the train, appreciates Dodson's craving of a quiet car.
—Jeanne Cooper, “Standing Up For More Train Seats,” The San Francisco Chronicle, October 31, 1997
Notes
With D2D's ridematching service, you may specify a "quiet car" that is free from chit-chat, freeing you for activities like working, napping, or relaxing.
—“Transportation Research Record,” National Research Council, January 01, 1974