Sentence:  Flange-stacked and cone-nosed, a Nashville, Chattanooga & St. Louis J-3 4-8-4 gives the <WSD>mail clerks</WSD> a look at the trim Alco as she leads the "Dixie Limited" out of Smyrna, Ga. 
Meaning of the word marked with <WSD> tags:  a person who sorts mail in a mail car on a train. (Post)