We recognize temperatures can be uncomfortable sometimes for riders on crowded trains, so we are in the process of replacing the heating, ventilation and air condition (HVAC) systems on the most problematic cars.

There are 230 “second generation” cars and these have far more HVAC problems than the 439 earlier generation cars that were modernized in the late ‘90s. In general, the problems are a result of the HVAC systems on these second generation cars not being designed to handle the extra demands of our increased ridership.

To address the problems, BART is replacing the HVAC units on all the second generation cars. The replacement project launched last year, HVAC units have been replaced on 40 cars and they continue at a pace of 12 cars per month. Our goal is to complete the replacements next year.

Looking ahead to the arrival of the Fleet of the Future beginning in 2017, the new rail cars will be even more efficient in keeping customers comfortable. They are designed for a capacity of 178 riders, feature microprocessor thermostats that much more responsive than the current sensors and will even be able to withstand outside temperatures of 110 degrees.

In the meantime, here are some tips that may help riders in stuffy conditions: