These huge rectangles each have two very large fans. These fans are attached to an open door at the end of a passenger car. This would be the door normally used by passengers to go from one car to the next. These fans generate tremendous airflow moving air rapidly through the car and out. Workers then use air under pressure to clean out vents and other areas throughout the train. This generates a lot of dust, of course, but these fans blow all the dust generated right out the back.
The photos in this slide show were taken in the mid-1990's by Steve Grande on his Amtrak travels throughout the nation. The size of the photos is purposely smaller as disk space was expensive and download speeds were slower at that time.
