Explaining the Grounds for Marriage Video Clip
Since no other information is available, we can only propose theories at this point.
The locomotives are the most obvious puzzle of this film clip. We know that Gilbert never offered F units in the 50's but could these be prototypes of proposed Gilbert models? Unless this sequence was filmed well in advance of its release, Alco PA's were in production as early as 1950 and were featured in that years catalogs, making it unlikely that supposed prototypes of a previous design were used. Finally, to my knowledge, there is no evidence that Gilbert ever considered making F units at that time, let alone created operating prototypes.
Enhorning Industries, however, was developing both F3's and F7's in S gauge at this time. They ran ads beginning in early 1950 through September of that year promising the arrival of an F3. Then in October of 1950, they advertised the availability of an F7. I think this is the most likely source of the locomotives in this movie. I tossed this around with several of my most knowledgeable friends and put it out for comment on the S-Scale group on groups.io. The general consensus was that these were indeed Enhorning Diesels. The only problem was that the trucks are clearly wrong for an EMD F-3 or F-7. Someone commented that he thought the trucks were Miller trucks. Miller Laboratory produced self contained power trucks from the 40's through the 60's, so they would have been readily available at the time of the movie. Miller was also well known for their S-4 Alco switcher which would have the type of side frames seen in the video. It is possible that only the bodies seen in the video were produced by Enhorning.
The video shows a 2 porthole A unit and the 3 porthole B unit, which is consistent with the 1951 photos of the Enhorning units that were eventually produced.
Conclusion: Enhorning bodies and Miller trucks.
Enhorning Model Railroader ads from September and October 1950
Enhorning Model Railroader ad from October 1951
Miller Model Railroader ad from January 1950
At first the cars don't seem that different from Gilbert cars, but on closer inspection they appear to differ in several ways from Gilbert items.
1. The baggage door windows in the combine are placed in line with the passenger windows, rather than above them as they are in Gilbert cars.
2. The combine passenger windows appear to be wider than the almost square windows on the Gilbert car.
3. No "American Flyer Lines" name plates are visible on any of the streamliners.
4. The rear end of the observation seems more squared off than the Gilbert observation.
Other than that, the length of the cars and the trucks seem consistent with Gilbert production.
As to other manufacturers whose products might have filled in for Gilbert cars, Chester Industrial Arts is one possibility. During this time, they made streamline passenger cars of wood with very thin and very shiny aluminum sheeting. They were available in O, HO, and S gauges.
Enhorning did make passenger cars but, assuming they were released to compliment the diesels, they would have probably been released after the diesels. The hybrid nature of the diesels we see in the film clip make me think that they are early or pre release products and that the cars would not have been available at the same time.
Another possibility is Midgage Models or Sylvania Models. Midgage was renamed Sylvania Models in 1950 when Gene Fletcher purchased the company. He only continued with the passenger car line. I think this is the most likely source of the cars. Catalog photos of the cars indicate a more squared off observation and a combine with baggage door windows on the same level as the passenger windows.
I am trying to get a better quality copy of the film clip and hopefully that will help us in figuring this out. If you can contribute any information, please email me at email@example.com.
Thanks to Emil Suda, Bill Drake, Daryl Olszeski, Richard Trotter, and the members of the S-Scale group on groups.io for their help in the preparation of this section.