That was originally a lyric from the "All Aboard America" jingle (it's at the beginning of the commercial I posted above), but it was later "extracted" to serve as a separate slogan. Here's a 1993 New York Times article that mentions it: TWA and Amtrak emphasize creature comforts, not prices
They should make a commercial this year using this one here:
They should replace the ending with a statement that they have been connecting america for 50 years.