The Montreal Metro's car fleet uses rubber tires instead of steel wheels.
As the metro runs entirely underground, the cars and the electrical system are not weatherproof.
The trains are 2.5 metres (8 ft 2 ³⁄₈ in) wide, narrower than the trains used by most other North American subway systems.
This narrow width allowed the use of single tunnels (for both tracks) in construction of the metro lines.

The first generation of rolling stock in Montreal went beyond just adopting the MP 59 car from the Paris Métro.
North American cities building metro systems in the 1960s and 1970s (Washington, D.C., San Francisco and Atlanta) were in search of modern rolling stock that not only best fit their needs but also encompassed a change in industrial design that focused on the aesthetics and performances.
Until June 2018, some of the Montreal trains were among the oldest North American subway trains in service – the Canadian Vickers MR-63 dating back to the system's opening in 1966 – but extended longevity is expected of rolling stock operated under fully sheltered conditions.

Unlike the subway cars of most metro systems in North America or Asia, but like those in most of Europe, Montreal's cars do not have air conditioning.
In summer, the lack of cooled air can make trips uncomfortable for passengers.
The claim, stated by the STM, is that with the Metro being built entirely underground, air conditioning would heat the tunnels to temperatures that would be too hot to operate the trains.
The Montreal Metro's car fleet uses rubber tires instead of steel wheels. As the metro runs entirely underground, the cars and the electrical system are not weatherproof. The trains are 2.5 metres (8 ft 2 ³⁄₈ in) wide, narrower than the trains used by most other North American subway systems. This narrow width allowed the use of single tunnels (for both tracks) in construction of the metro lines.
The first generation of rolling stock in Montreal went beyond just adopting the MP 59 car from the Paris Métro. North American cities building metro systems in the 1960s and 1970s (Washington, D.C., San Francisco and Atlanta) were in search of modern rolling stock that not only best fit their needs but also encompassed a change in industrial design that focused on the aesthetics and performances. Until June 2018, some of the Montreal trains were among the oldest North American subway trains in service – the Canadian Vickers MR-63 dating back to the system's opening in 1966 – but extended longevity is expected of rolling stock operated under fully sheltered conditions.
Unlike the subway cars of most metro systems in North America or Asia, but like those in most of Europe, Montreal's cars do not have air conditioning. In summer, the lack of cooled air can make trips uncomfortable for passengers. The claim, stated by the STM, is that with the Metro being built entirely underground, air conditioning would heat the tunnels to temperatures that would be too hot to operate the trains.
Montreal Metro