Montreal is well covered by its subway system, the Metro . There are 65 stations on 4 lines. Map here. The transfer stations are identified with big white dots on the map. The oldest and main transfer station is BERRI / UQAM ( UQAM stands for: Université du Québec À Montréal). Single fare is $2.75 CAD. You can buy  a 6-ticket strip for $11.75 CAD and a weekly pass (unlimited) for $19.00 CAD. The weekly pass goes from Monday to Sunday. There are also 2 Tourist Cards: a 1-day card costs $9.00CAD, and a 3-day pass costs $17.00CAD; details about the Tourist Cards may be found  right here  . Children under 5 ride for free, as do people with disabilities along with a person travelling with them. Children between 6 and 11 pay a reduced fare.

The most important subway lines are the GREEN and the ORANGE. The shortest line is the YELLOW LINE, joining Berri-UQAM to Longueuil station; this line allows you to reach Parc Jean-Drapeau and La Ronde Amusement Park on Ste-Hélène Island. This is the stop if you want to go to the Formula 1 Grand Prix in the summer. 

The BLUE LINE serves mainly  Université de Montréal, and also one very popular food market: Jean-Talon.

The GREEN LINE covers the downtown shopping area, three of the universities (McGill, Concordia, UQAM), the Botanical Gardens, the Insectarium, the Olympic Stadium. 

The ORANGE LINE covers Old Montreal, the Plateau Mont-Royal area , the St-Denis Street shopping district and the HI Youth Hostel (hostel at Lucien-L'Allier Station, but also within a walking distance of the Guy-Concordia Station, green line)

The so-called Underground City is mainly the downtown area where lines 1 and 2 are parallel: between Place-des Arts and Place d' Armes and between McGill and Bonaventure stations.

The subway opens around 5h30AM and closes around 12h30AM (a little later during the weekend).

A list of the bus stations accessible for wheelchairs can be found here , and more information here . The métro is also accessible to bicycles .

Free transfers between subway and bus . Some areas of interest can be reached by a combination of subway and bus. Once you've paid your fare in the subway or a bus, you can take a transfer ticket valid for 90 minutes. The transfer ticket is available in electronic distributors after the cashier's cabin in the subway or by request from the bus driver after you've paid. You don't need transfers if you bought a weekly pass. You may transfer from bus to subway or from subway to bus as long as you are travelling in one direction (no coming back on the same ticket\transfer).

If you realize you are waiting for the subway on the right line, but in the wrong direction : don't panick, no need to pay again : just walk your way back up the stairs, or the escalator, and head in the proper direction, without exiting at the paying booth.

A few examples where the subway + bus combination is useful :

• Parc du Mont-Royal (mountain in the middle of the city): subway station Mont-Royal on line #2 + bus #11
• Schwartz Delicatessen on St-Laurent street: subway station St-Laurent on line #1 + bus #55

INFO LINE   If you are in Montreal and do not know which bus you should take, or subway station, or which combination of the two, you may call A-U-T-O-B-U-S (288-6287) . The information service is available in French and English.

You may look at, and eventually download (PDF files),  MAPS (including a map of the Underground City) of the network  here

COMPREHENSIVE MONTREAL METRO'S FAN SITE : everything you wanted to know about the metro system, or still want to know after reading all of the above lies in here  .