Sentence:  ‘Good evening, good evening,' Father Rank called. His stride lengthened and he caught a foot in his soutane and stumbled as he went by. ‘A storm's coming up,' he said. ‘Got to hurry,' and his ‘ho, ho, ho' <WSD>diminished</WSD> mournfully along the railway track, bringing no comfort to anyone. 
Meaning of the word marked with <WSD> tags:  To disappear gradually.