Yes. Even if they ran multiple trains on the branch, I never heard of them described in plural. There was a joke line about “the dinky that meets all the trains” that went with the Don Marquis poem.
For those who may not be familiar with the reference, here’s a cartoon with some of the flavor:
But as a note I never remember seeing Princeton Junction & Back trains operate with ‘one car’ when using MP54s, which it did well into the 1970s, although admittedly my exposure to it was small and periodic (football games and reunions, as a child) during the octagonal-wheel days of the PRR, when mechanical ‘difficulties’ might have made it expedient to run two at a time for redundancy; it’s possible these might have been motor-trailer pairs. Thereafter the service ran with a single Silverliner under Penn Central before Conrail, initially I think with cars in the low 200s. (I got to see the very last two-car MP54 Dinky move south on the main after it was relieved in that service.)
I don’t now remember if I saw married-pair Silverliners ever used in this service, but that would be an exception for peak traffic times.
Also, rmember that in the summer of 1952, I am certain I did not see GP-7s on suburban trains on weekends. Only off-peak on weekdays and reverse peak during rush hours. And then sporadically, not regularly, not the same train every day. Most railfan pictures are taken on weekends and not on weekdays. I also seem to recall that GP-7 sightings were more toward the beginning of the summer than toward the end.
Based on the assumption that GP7’s on Burlington commuter service were only an occasional occurence in the 1950’s, also keep in mind that this was a time when many railfan photographers had little to no interest in diesels and a lot of things that we would find quite interesting were totally ignored. I would agree that GP7/9’s on a commuter train DID happen, but a photograph of such an occurence would be unlikely.
Just a reminder, remember to get pictures of what’s new or you might regret it later.