 The fans are mounted above the ceiling of each vestibule and force fresh air into a ventilation duct which runs above the ceiling along the car centerline and feeds the air into the passenger salon via a series of small vents.In the summer the air is taken in through outside air intakes and passed through screen filters; in the winter the air is partially recirculated.Heating is provided by electric heating under the bench seats (intermediate trailers and power cars usually have 20 furnaces, driving trailers 14).