There will be 50 fewer streetcars on Toronto streets at rush hour today due to the extreme cold.

The TTC says it normally operates about 195 streetcars during peak service, but during extreme wind and cold warnings that began Friday morning, it was short 48 streetcars.

By rush hour, the number of streetcars out of service was 50.

Buses will travel the routes affected by the missing streetcars.

"The age of the streetcar fleet and equipment – over 30 years in many cases – does not respond well to extreme cold," the TTC says in a release. "Specifically, pneumatic air lines that provide braking and door operation can see moisture build up in the lines that then freeze, causing the streetcar to be taken out of service."

Newer streetcars, which use electrical and hydraulic, are not as troubled by extreme cold. Testing of the new fleet began in August but it will take six years to fully replace the older cars.