D&RGW GS Gondolas
The following comes from an email from Jim Eager, dated June 25, 1998:
This is the first of a possible series on existing models that are accurate for (or at least close to) various Rio Grande freight cars. This post is a bit longer than I had intended because of the modeling notes.
Since the Grande long relied on a fleet of steel drop-bottom GS gons for coal service, naturally modeling them would be a high priority, so let's start with them.
At first glance, modeling the Grande's GS gons might seem to be almost entirely an exercise in frustration. While the Grande rostered 8,531 steel GS gons of 10 distinctly different designs, there are no kits or brass models specifically based on a Rio Grande prototype in any scale. For instance, the old Ulrich die cast metal kit in HO is based on a 1920s-era Enterprise car widely used by the SP and UP, but not by the Grande. Likewise, both of the kits made by Details Associates are also specifically based on SP prototypes.
DA's composite wood & steel truss kit is similar to the Grande's 71000-71999 series built by Pressed Steel Car in 1943, but those cars were 6 feet longer and approximately 4-6 inches taller, plus they had very different ends from those supplied with the kit. (There is an N scale model of a composite GS gon as well, but I can't remember the manufacturer.) DA's all-steel kit is similar to the Grande's 72000-73699 series built by General American in 1953-54, but those cars were also 6 feet longer and taller, plus their Dreadnaught ends had 5 ribs verses the kit's 4.
But take heart, all is not lost because the DA all-steel kit is quite close to the Grande's 46000-46499 series built by Pressed Steel in 1947-48. Inside length was 42-9 verses 41-0 for the SP prototype, or 40-6 for the model. 2 feet 3 inches is a lot less of a difference than 6 feet, and inside height was the same at 5-0. The Rio cars also used the exact same Dreadnaught end that is supplied with the kit, although there were some other differences.
First, the Rio cars had Duryea sliding center sills. While it may seem irrational to put a cushioned underframe on a car designed for coal and aggregate service, the idea was that the spring cushioned sills would handle much of the train stresses (slack action & buff), sparing the carbody itself, thus increasing its service life. A good idea, but the Duryea system wasn't up to it and premature wear and failures led to the retirement of the cars en mass circa 1972.
Another difference was that the end sills on the Rio cars sat behind the end sheets, while the SP car's end sills were outside the ends. This is fairly easy to fix by filing the end sills and the underframe so that they fit flush with the ends when assembling the car. As a bonus, the draft gear pockets will then project further out just as they should. The other main feature of the Duryea underframe is that all of the cross bearers are deep, like the larger ones in the kit. Just make some more to match using sheet styrene.
The doors supplied with the steel kit are the flat type, where the Rio cars had ribbed doors, but DA sells their ribbed doors separately (part no.6223). The ribs were not quite the same, but they will be closer. The last major difference was that the Rio cars did not use the Enterprise link system for the doors, but regular chains instead. Builders in Scale makes 40 link-per-inch chain that can be used to simulate this feature. Champ's HN-4 roadname set and HD-23 gon data set can be used to decal the cars. I use sheet lead cut to fit into the bottom of each door and in the center sill to give the car some weight.
That covers the main modifications needed to model the 46000-46499 series using the DA kit, although there are a number of smaller detail differences as well. Unfortunately there are very few published photos of these cars to refer to. There is a builders photo of no. 46399 in the 1953 Carbuilders Cyc, and the photo can also be found in the November 23, 1953 issue of Railway Age, p.34. The 46500-46999 & 47000-47499 series were identical except for the ends, and a photo (dark) of 47139 is on p.76 of the Color Guide. The Grande sold 75 cars to the SP&S in 1965 for woodchip service, and the SP&S Color Guide has 2 or 3 good photos of them as well.
Although accounting for only 500 cars used in the 1947-1972 period, that's about it for HO models of Rio Grande GS gons that are at all close.