There's an old saying about Beijing that "It's a city where one has to force his way in."
For Zeng Yuanpeng, the same goes for the Beijing Subway.
Every morning, Zeng joins the crowds flocking into the Tiantongyuan Subway Station, which links one of the largest residential communities in Asia to the urban centre of the capital.
At 23 years old, he came to Beijing to start his life after graduating from a university in Northeast China.
Tiantongyuan, some 20 km away from downtown Beijing, is nicknamed the "sleeping city", because many residents work in the city and go to bed as soon as they arrive home outside the Fifth Ring Road.
Zeng is one of the more than 400,000 people who live there, migrating in mass numbers to Beijing each day to work.
Like every newcomer to the Beijing metro, the first time Zeng walked into the subway station he hesitated in front of the crowds forcing their way into the carriage.
After several trains, the lines waiting on the platform still seemed endless.
He realised finally that law of the jungle reigns in subway station. If he kept being a gentleman, he would never get on the train. To avoid being late, he ditched his manners and forced his way into the carriage.
Subway veterans had worked this out years ago and included similar tactics in the Beijing Subway Survival Handbook.
One of the tips is: "First: put your feet in the carriage; second, firmly grasp the handrail overhead; and third, cram you body into the carriage."
Even the strong and youthful Zeng once had his pack stuck between the closing doors of the carriage. He took it with composure, saying "Even if you are stuck between the doors, you must not lose your head because it will not close if anything stands in between."
Zeng and other passengers aren't the only ones involved in the daily push for space. To help passengers board the trains before the doors close, special subway staffers are assigned to push those left behind into the carriage.
Li Siye, who works as a "pusher" on Line 13, told Beijing Daily her first job was at Xi'erqi, a metro station where 300,000 commuters pour in every day,
Li said: "When the door opened, people flooded into the carriage. I was almost knocked off my feet. When I raised my head, there was a young man, holding the handrail with both hands, one foot in the carriage and the other outside, and trying to get into the carriage. He shouted 'What are you waiting for! Push me. I am late!'
"He shouted at me until he was blue in face."
Beijing's already overcrowded subway system faces ever more pressure, forced to accommodate the half a million people who settle in the city each year.
The government is racing to keep track of the ever-growing population. It is estimated that by 2020, Beijing will have invested 400 billion yuan (S$86 billion) on rail traffic.
By that time, Beijing will have a railway network of over 1,000 km, the longest in the world.
Recent fare hike is another way to reduce the passenger flow, but some are sceptical about the increase.
"Metro fare hikes will not solve the problem. The hike will cut the passengers taking metro by 30 per cent, but those scared away by the high price will take alternative transport vehicle above the ground where traffic is still crowded," said Wang Mengshu, an expert of underground engineering and a member of Chinese Academy of Engineering.
Wang continued: "The primary reason for traffic jam is the unreasonable urban planning. For years, 'build the house first and then pave road' was the mainstay among city planners. It wasn't until recent years that they started realizing that metro planning and city planning should be considered as a whole."
He cited Metro Line 5.
The line that crosses the city from north to the south was incorporated into the city's overall planning in as early as 1981, but its construction wasn't started until 2004 and finished in 2007, spanning 26 years.
During the period, the city's population had nearly doubled.
Although Zeng Yuanpeng, who earns a monthly salary of 3,000-4,000 yuan (S$645-860), is sensitive to the metro price, he is a staunch supporter of metro.
The reason is simple: bus is unpunctual due to congested roads.
"The subway is the mirror of this competitive city: one must exert his full effort to become part of it. Fight or wait. And I don't want to wait," said Zeng.