Commuters who use the MBTA's Red Line are being urged to seek alternate ways of getting to work.

A T spokesman said Tuesday that a week of constant exposure to frigid temperatures, ice, and snowfall has taken a toll on vehicles and infrastructure.

The National Weather Service says temperatures early Tuesday could fall to 17-below with wind chill.

Although all T modes are being affected, the Red Line is a particular issue because of a shortage of fully functioning subway cars.

A six-car Red Line train with about 50 passengers was stranded for about two hours on the tracks near the Braintree station on Monday. T spokesman Joe Pesaturo said major disruptions in both directions occurred when the third rail lost power from Quincy to Braintree about 4:30 p.m.