In a city of 20 million, the metro system is the main people mover. a subway ride offers a sneak peak of the diversed culture

What's the last thing you'd expect to see on the subway at 5 am, amid people trying to get comfortable on the hard plastic seats to catch a few more winks before work?

For me, it was a young woman applying full makeup, from foundation to lip gloss to false eyelashes. The pre-dawn, underground beauty ritual looked like a daily routine because she spared not a single glance for staring fellow passengers, primarily me.

But the scene really shouldn't have come as a surprise. Although the number of cars in Beijing has risen to 5 million, all manner of people in the city of 20 million still rely on the subway to get around. After all, it's cheap and far-reaching.

Two yuan (0.21 euro) gets you to and from any of the capital's 160 subway stations on the 11 lines currently interconnected. (The Airport Express line charges 25 yuan to take travelers to the Beijing Capital International Airport.)

If you have a day with at least 15 hours to spare, 2 yuan can get you to all the subway stations. There's no time limit on the tickets, so passengers can stay within the subway grid for as long as they want, from 5 am till 11 pm.

Just remember to pack breakfast, lunch, dinner, snacks and drinks because food and beverages aren't sold inside Beijing subway stations. The only vendors you'll see are those selling newspapers, magazines and tourist maps.

Taking the subway is also the best way to beat Beijing's traffic jams, especially during the 7 to 9 am and 5 to 7 pm rush hours. Travel time between stops is 1.5 to 2.5 minutes on the lines around the city center, and 2.5 to 3.5 minutes in the suburbs. During the busiest hours, the waiting time between train arrivals goes down from 8 to 2 minutes, but be prepared to shove and be shoved, squashed and squeezed by the masses making their way to work or home.

Don't take the physical abuse personally; this is standard procedure in a city as crowded as Beijing.

For tourists and residents who don't speak Chinese, the subway is a convenient way to reach locations outside the city center, such as the Beijing South Railway Station and the International Exhibition Center. Plus, the subway platforms are relatively clean, the washrooms in newer stations have toilet seats installed and the carriage seats on Line 15 are heated in winter.

Unfortunately, the Beijing subway isn't for everyone.

Its biggest weakness is accessibility for the disabled. Those who use a wheelchair, and those who have trouble walking or seeing, will have great difficulty getting in and out of older stations that do not have elevators or wheelchair lifts. Transferring between lines will also be tricky for them, since this involves navigating a combination of long walkways, ramps and flights of stairs.

In fact, some women in high heels already have difficulty walking up and down Jianguomen and Dongzhimen's somewhat slippery and bumpy transfer ramps. In the four years I've been in Beijing, I've only seen wheelchairs on the subway once or twice.

It would also help to have more transfer stations, particularly in the subway network's southern end. That way, people can save on travel time - and those who have nothing better to do than spend 2 yuan riding all of the city's subway lines can actually be home for the last meal of the day.