Sentence:  He took a <WSD>midnight</WSD> train out of Cleveland Saturday , without an official word to anybody , and has stayed away from newsmen on his train trip across the nation to Reno , Nev. , where his wife , former Olympic Diving Champion Zoe Ann Olsen , awaited . 
Meaning of the word marked with <WSD> tags:  12 o'clock at night; the middle of the night