Subway guards, the early-20th-century forerunner of today's platform controllers, were posted at busy stations the last time the system had this many riders, during the Great Depression and World War II era. That role, The New York Times noted in 1930, required the skills of "a football player, a head usher, a stage director, pugilist, circus barker and a sardine packer."
That year, the city's health commissioner criticized the "indecency of present overcrowding" and warned of protecting riders from contagious diseases. A video from the New York Transit Museum's archive shows subway riders scrambling onto crowded trains in the 1940s.
Another big city currently grappling with huge crowds is London, and there the Tube has taken drastic measures: Stations simply close when they get too crowded. The busy Oxford Circus station in that city's West End was closed more than 100 times over the course of one year, officials said, leaving hordes of riders to mill about at street level.
It is difficult to imagine New Yorkers patiently waiting at roped-off subway entrances.
Kevin Ortiz, a spokesman for the authority, said such restrictions were not necessary in New York City — at least for now.
"At this point, we don't feel there are any current safety issues associated with overcrowding, but it's something we will continue to monitor as ridership grows," Mr. Ortiz said.
The authority has weighed several proposals, including buying trains with open pathways between cars that can carry more riders and installing platform safety doors, like those on the AirTrain at Kennedy International Airport, to serve as a barrier to keep riders from falling onto the tracks.
Brussard Alston, a train operator for nearly two decades who has worked on the C line, said operators were instructed to approach crowded stations slowly, at about 10 miles per hour.
"When you're bringing the train into the station and you see the station is packed, you always have that on your mind — the possibility that somebody could be pushed or someone could fall or trip or faint," Mr. Alston said.
At the 86th Street station, riders stood away from the platform edge because of such concerns. Parents with young children held on extra tight.