I have a November 1958 Official Guide; here is the consist as listed for train #168, The Montrealer:
Sleeping cars [Car # 1687]: Washington to Montreal [berths, bedrooms, roomettes] - from PRR #152 at New York.
Car #s 1684-1686, inclusive - New York [Penna Station] to Montreal [berths, bedrooms, roomettes, buffet lounge]
Dining car - Washington to New York [Penna Station]
Coaches - Washington to New York [Penna Station]; New York [Penna Station ] to Montreal
Train #169 - The Washingtonian:
Sleeping cars [Car #2008] Montreal to Washington [berths, bedrooms, roomettes] [to PRR #115 at New York]
Car #s 2005-2007, inclusive - Montreal to New York [Penna Station] [berths, bedrooms, roomettes, buffet lounge]
Dining car - New York [Penna Station] to Washington
Coaches - Montreal to New York [Penna Station]; New York [Penna Station] to Washington