The Mexico City Metro.
Officially named Sistema de Transporte Colectivo, but known simply as El Metro, it is one of the largest and most used subway systems in the world, with 11 different lines that measure more than 170 km and carry 4.4 million people every day to various parts of the city.
If you plan on using the metro, you will quickly see how busy it is and during the day: trains are often filled to full capacity whilst passing through main stations in the "downtown" areas or more centrally located areas.
The metro is quite quick and very efficient, with trains every few minutes and is a good alternative to taxis during rush hours when the city traffic is very heavy.
The metro in Mexico city is the worlds cheapest rail system at $2 pesos per ticket with unlimited line changes within the system .
Trains run every couple of minutes, so if you just miss one you won't have long to wait until another arrives and the Metro can be the quickest way to travel longer distances within the city. For example, Lindavista to Xochilmilco (which would take an hour by car with traffic)
Stations usually have food stalls,newpapers,small bakeries,take away pizzas inside and outside the entrances and many metro stations have city-sponsored exhibits and artwork on display,usually relating to the metro systems in different parts of the world, mexican art, history etc.
Operating hours are from 5AM to midnight on weekdays (starts at 6AM on Saturday and 7AM on Sunday) if you plan to be out later, remember to make other plans to get back to your hotel. (Also see safety blog about using the metro at night).
Although the thought of using the metro in a foriegn country may scare you, dont be too afriad. the Metro does not have any informational signs in English, but the system was originally designed with illiteracy in mind as many people did not read or write. So finding your way around should not be a huge problem.
Metro Lines are defined by number but also by a color, and that color runs as a thematic band across the entire station and along the entire route, so you always know what line you are on. Look up and you will see what im talking about ... you will see a coloured band and usually a name of the station on it.
Stations are identified by name but also by a pictorial icon (due to illiteracy) with each symbol/icon representing the area of the stop in some way. (Look at photos below for example).
So you have numbers, colurs, names and pictures to help you find your way ! However, even with this user-friendly approach, entire maps of the Metro system are not posted everywhere, they are usually only near ticket booths, there are no maps on the trains and only rarely posted on the platforms, so work out your route before going through the turnstiles. (Inside the Trains and platforms they do have a line diagram with icons and transfer points for easy reference) but maybe a good idea would be to get a copy of the map located on this page below.
Some lines run through more tourist-related spots than others and will become very familiar to you after a while using the system.
Line 1 (pink) runs through many tourist spots, such as Centro Historico (Salto del Agua station), the Chapultepec Forest (Chapultepec Station), Condesa and Roma neighborhoods (Insurgentes and Sevilla stations) and the Northwest Bus Station (Observatorio station).
Line 2 (blue) runs through the Centro Historico (Allende, Zocalo and Bellas Artes stations) and reaches the South Bus Station (Tasqueña).
Line 7 (orange) runs through many 
touristic spots such as the Chapultepec Forest (Auditorio Station) and the Polanco neighborhood (Polanco Station).
Line 9 (brown) runs near the Condesa neighborhood (Chilpancingo).
Line 3 (green) runs near Coyoacan (Coyoacan and Miguel Angel de Quevedo stations) and also near the City University (Copilco and Ciudad Universitaria stations).
If you are traveling to and from the airport, you'll use Line 5 (yellow) to connect to the Mexico City International Airport (Terminal Aerea station).
Here are a few of the commonly-used Metro signs translated into English:
- Taquilla - Ticket booth
- Entrada - Entrance
- Salida - Exit
- No Pase - Do not enter
- Andenes - Train platforms (both directions)
- Correspondencia - Line transfer
As you enter a Metro station, look for the ticket booth, there will be a sign "TAQUILLA". There might be a queue for tickets and to avoid having to always stand in line most people buy a small handful of tickets at a time. Remember each ticket is valid from entering to exiting any two stations no matter how many lies you change, from one point to another so to come and go back to your point of origin, you will need 2 tickets and so on.
A sign is posted by the ticket window that shows how much it would cost for any number of tickets. Once you approach the agent (who are famously unfriendly) simply drop some money into the tray and ask for (in Spanish) how many tickets you would like ("uno" for $2, "cinco" for $10, "diez" for $20, and so on). You do not need to say anything about where you are going, since fares are the same for everywhere in the system.
Once you have your ticket (boleto) it is time to go through the turnstiles (but make sure to confirm your route on a map first!). The stiles are clearly marked for exit or entry but if you are confused, simply follow the crowd. Insert the ticket into the slot (it does not matter which direction is up or forward) and a small display will flash, indicating you may proceed. You won't get the ticket back. A few frequent Metro users use keycards instead of tickets, so if you see any turnstiles marked with "solo tarjeta" that means the ticket reader is for cards or may simply be broken; just move to another turnstile.
Past the turnstiles, signs that tell you where to go depending on your direction within the Line are usually clearly marked, as are signs that tell you where to transfer to a different Line. There is no standard station layout, but they are all designed to facilitate vast amounts of human traffic, so following the crowd works well, as long you double check the signs to make sure the crowd is taking you in the same direction.
*TIP... when you pass into the metro you will see signs directing you to the different platforms based on which direction you want to go. Usually these "directions" will read as the last stop in either direction not the next stop from the current station(a litle confusing at first)
See the map and check my explanation here . For example, if you are at Merced on line 1 wishing to get to chapultepec, you will enter to metro and proceed for the direction advertised as observatorio (end of the line) and not the next stop.
On the platform, try to stand near the edge. During rush hours when it can get pretty crowded, there is sometimes a rush to get on and off the train. Although for the most part people are respectful and usually let departing passengers off first, train doors are always threatening to close and that means you need to be moderately aggressive if you don't want to get left behind. Dont worry, in busier stations transport polce patrol the platforms incase of aggressive behaviour so it should be anything to worry about.
If you are traveling in a group this could mean having to travel separately sometimes if some of you dont get into the same train. At the ends of the platform, the train is usually less crowded, so you should probably wait there, but during rush hours some busier stations reserve those sections of platform exclusively for women and children for their safety.
While on the train, you will see a steady stream of people walking through the carriages announcing tings for sale. Its not advisable to buy anything as its not good to risk taking out your wallet in the metro.Ignoring the sellers is not considered rude in Mexico but you may ask you to let them pass if the metro is busy.
Most often you'll see the city's blind population make their living by selling pirate music CD's or DVDs,but an increasing number of young people are doing thing, blaring their songs through amplifiers carried in a backpack.
There are also people who "perform" (such as singing,playing instruments or the worst which i have seen and thankfully only once, repeatedly somersaulting shirtless onto a pile of broken glass) they expect a donation but you are not obliged, have some spare 25cent coins in your outside pocket maybe. There are also people who hand out candy,chewing gum, pens or papers/poems during stops and if you eat it or keep it you are expected to pay for it; if you don't want it, they'll take it back from you at the next stop. The best thing to do is observe how others around you behave, but you can usually just avoid eye contact with these merchants and they will take the product back from you and leave you alone. I´ve never been pestered to buy something ever.
If the sellers weren't enough, the trains are usually just crowded places to be. You will usually not get a seat if you are traveling through the city centre during the mid day, and even if you do, it's considered good manners to offer your seat to the aged, pregnant or disabled, as all cars have clearly marked handicap seats. In keeping with the mad rush on and off the train, people will move toward the exits before the train stops, so let them through and feel free to do the same when you need to (a "con permiso" helps, but body language speaks the loudest here). I find that its best to keep near the doors unless you are taking a long journey on the same line.
Tthere have been incidences of pickpocketing like in all metro systems so keep your belongings close to you; if you have bags, close them and keep them in sight. As long as you are alert and careful you won't have any problems. I have never had any problems in the metro.
When exiting, follow the crowd through signs marked Salida (exit) . Many stations have multiple exits to different streets (or different sides of streets, marked with a cardinal direction) and should have posted road maps that show the immediate area with icons for banks, restaurants, parks and so forth. Use these to figure out where you need to go.
All in all, i dont think that the metro system does a bad job or is unpleasant when you consider the size and the amount of people it carries daily for such a small price.
* Safety Advice
You should check out the blog on safety before travelling but it is not advisable to use the metro late at night especially if you are travelling alone.
Metro Update :
In Aug. 2007 the construction of Line 12 (golden line) was officially announced. It will run from Mixcoac (Line 7) to Tlahuac in the southeast of Mexico City, intersecting with line 3 at Zapata, line 2 at Ermita and line 8 at the future station Del Paso. Although initially planned to be entirely underground, Line 12 will be finally be underground only along its western half, while the rest will be partly at grade and mostly elevated. The total length of the lines is 24.5 km with 20 stations. The eastern surface strecth is scheduled for completion in May 2011, and the western underground stretch in May 2012.
