Sentence:  We expressed our readiness, and in ten minutes were in the station wagon, rolling rapidly down the long drive, for it was then after nine....As we reached the lodge we heard the <WSD>whistle</WSD>, and we backed up against one side of the platform as the train pulled up at the other. 
Meaning of the word marked with <WSD> tags:  (sound) A shrill, high-pitched sound made by whistling.