Pieter Roos provided us with the text and photos of how he built this car. All photos are copyright © Pieter Roos; used by permission.
I ran into an A.F. hopper body my Dad (an accomplished S-scale modeler himself) had worked on. He had filled in the top offset with plastic and putty and added ACE conversion bolsters, maybe planning to make a rib-sided car, before American Models came out with theirs.
My other inspiration was Frank Titman's article on hopper conversions in the Mar/Apr 1984 S-Gaugian magazine. I own one of the cars shown in that article, the D&H composite triple-bay hopper, bought in 2013 when Frank's family sold his equipment at the NASG Scranton convention. I really liked the way he built things that he wanted, simply, at a time little was available in S.
I decided to make an Eire/NYS&W horizontal ribbed car as something different. I'm not sure I've seen one in S-scale; in HO-scale there was an older wood kit by Ambroid, and F&C presently offers a resin version.
One distinctive feature is the triple flat-bottom hopper doors, which meant I had to cut back and plate over the Flyer hoppers with styrene.
The photo on the right shows the model under construction, on top of an old Railroad Model Craftsman Plan Book.
Better plans were made for the Ambroid wood and card version in both O- and HO-scale, but I didn't have access to those, and trying to get too close to the prototype with the A.F. shell base would be frustrating.
This is more of a "look at pictures and make something that appears correct" project, rather than a measure-and-scale project.
I did find some photos on the O Gauge Railroading On-Line Forum.
There is a prototype photo on the RPI club Facebook page (see their first photo).
The November 1988 issue of Mainline Modeler had an article and S-scale drawings for the car.
The photo and drawing show hat section ribs in the Plan Book, but later versions used Z-section ribs. This should be a very distinctive car in a train of common ribbed and offset hoppers. Going from memory, Erie built 2,000 of these cars, and another 1,000 for its subsidiary NYS&W. About half with "hat section" ribs, the rest with Z-section ribs (represented on my car).
To actually construction this car, I measured down 18 scale inches vertically from the bottom of the car side to cut the hopper bottoms. I plated over the flat bottom that resulted with 0.020 styrene cut to fit. Another piece of 0.030 styrene sheet cut to width but a bit (about 1/8th inch) longer was then cut into three equal parts, each scribed and bent slightly in the middle, to form the three sets of doors.
New hopper sides were cut to fit. Door ratchets are sections of sprues and an NBW casting inserted into holes drilled in the hopper sides. Ribs were 0.060" square styrene strips, with 0.010" x 0.040" strips for the flanges. The bottom side flanges are from 0.020" x 0.040" strips.
For paint, I used Testors acrylic gloss black. Decals were patched together from Enhorning S-scale Erie roadname with Champ HO-scale herald and various bits of data. Finally, the weathering was done with Floquil rust and a home-made grimy black from Engine Black, Rust, Primer Gray, and Brown, highly thinned.
A better model would result from cutting back the body ends (not the frame) by 1/8th inch and adding new ends and finer uprights, and a vertical brake staff. Also removing the bulb angle (the lip around the top of the body), and add lots of Archer rivet decals, as well as frame corner braces and slope sheet braces.