I know the"that ain't prototype" line is usually disproved at some point, but hi-railers no doubt hear it from other hobbyists more than most. Now then, a prototype for the Lionel FT passenger set? Here's something close.
I found a photo of a Boston-Montreal CP passenger train in a Hamilton Ellis book. It shows a single-unit diesel, maybe F or E unit, and three cars; baggage/mail, chair car, and an open-deck observation, an almost-match for the Lionel set.
Closest I can find online are the CPR and B&M trains below:
https://www.pinterest.com/pin/268879040227264681/
http://www.trainweb.org/oldtim...hotos/us/BM_3807.htm
I only stir the pot like this because a childhood train I rode regularly operated with one locomotive and one passenger car, period.