Phoebe Snow trip times Hoboken - Chicago per EL's October 30, 1966 passenger timetable ("the Friendly Service Route"):
wb: Train #1 departed Hoboken at 10AM EST (and Dover @ 11:03) and arrived Dearborn St station in Chicago at 8AM CST for a trip time of 23 hours.
eb: Train #2 departed Chicago @ 6:30PM CST and arrived Hoboken at 6:20PM EST for a trip time of 22 hours 50 minutes (The Phoebe must have enjoyed the same west to east tailwind as do eb flights).
Sadly the Oct '66 tt has a note appended to the Phoebe's schedule " Trains 1, 2, 21, and 22 are subject to discontinuance...."
For comparison, in the December '63 EL tt, the wb Phoebe running as trains 1-31 (#31 was the Hornell to Buffalo connection) ran 15 minutes quicker.
In 1970, un-named PC #61 ran NYC to Chicago via Buffalo in 18 hours and the Broadway Ltd #49 ran via Pittsburgh 18 hrs, 45 minutes.
Lastly, in July '58 the DL&W/NKP ran the Phoebe/City of Chicago between Hoboken and Chicago in 22 hours.