Thursday, December 1, 2011

Modeling the Glasshopper II

In the mid-1980s, when I lived in Pittsburgh, I participated in a project of the Pittsburgh Model Railroad Club (as it was then named), to build a small demonstration layout for the Lord Corporation of Erie, PA. Lord produced a number of railroad-related products, from rubberized grade crossings to a wide variety of coatings and linings for freight cars. They wanted a small HO scale layout which would feature their products, for publicity purposes.
     The club set to work on this project, and produced a nice portable layout which I understand Lord did use, taking it to various conventions and so forth. One part of the project I worked on was to produce a model of the fiberglass covered hopper called the “Glasshopper.” Lord not only supplied an adhesive used in the car’s construction but also the polyurethane coating used on the outside. So what the heck was a Glasshopper?
     The Glasshopper story had started back in 1973, when a severe car shortage caused James Springrose, then Vice President-Transportation for Cargill, to think about ways to increase payloads and thus need fewer cars. From then until 1978 Cargill worked on its own toward development of a lighter car body for covered hoppers, with fiberglass uppermost on the list of materials.  
     In 1978 a joint venture between Cargill, Southern Pacific, and ACF 
Industries was created to build a prototype car, named the “Glasshopper,” 
based on Cargill’s ideas. The novelty in construction was that long fiberglass filaments were wound onto a large mandrel to make a one-piece car body of otherwise conventional polyester-fiberglass material. This is in contrast to most of the familiar fiberglass products one sees, which use chopped (short) glass fibers in a polyester matrix. The goal of the Glasshopper project was a tare (light) weight of 52,000 pounds, well below that of other 100-ton covered hoppers. 
     The production process was dramatically different from other freight cars in that innocuous-sounding phrase, “one-piece car body.” The mandrel for the filament-winding process was the size of the complete car body. Here is an ACF photo of the process, which was carried out at ACF. Fiberglass pressure vessels can be fabricated this way too.

Once the basic body was completed, final assembly, including steel side sills and bolsters (the Center Flow design has no center sill), was accomplished at ACF. There was a detailed story about the first car in Railway Age for 30 March 1981 (pages 56 and 57), when it was put into service. 
     The car was considered very successful, holding up well in service with a variety of loadssome of them corrosive. An additional unplanned test occurred in August 1982, when the car was involved in a derailment which included several other cars. As a spokesman for the joint venture put it, “the impact created by the derailment was such that it broke the Glasshopper’s coupler shank and caused the car to skid several hundred feet, leave the track, and slide down an embankment on its side. The car was righted, re-trucked, and returned to ACF’s Technical Center in St. Charles, Mo. for evaluation and minor repairs. These repairs primarily involved steel components such as ladders and outlets. The FRP (fiberglass-reinforced polyester) body was virtually unharmed.” (from Railway Age, January 1984, page 28)
     Here is a photo of the car being retrieved from that derailment (photo courtesy Lord Corporation); note the upper left logo of Cargill, SP and ACF.

The Glasshopper was part of an imagined “new age” of freight car design, judging from the slightly breathless article by Railway Age senior editor Gus Welty, entitled “The new breed of freight cars: A material difference.”  (Railway Age, May 25, 1981, pages 26-29)
     The experience with the Glasshopper led to modified specifications for Glasshopper II.  The original car was “somewhat conservative” in design, according to ACF, and still lighter weight was targeted.  In addition, a cleaner interior design without bulkheads was considered feasible. The new car was announced as entering service in January 1984, although its “built date” was April 1983 (testing was conducted in the interim). Like the original Glasshopper, it superficially  looked much like a conventional ACF Center Flow covered hopper, although its 15' 6" height put it into the “Plate C” extra-height category, and was again a one-piece filament-wound FRP body.
     Here is a three-quarter view of the Glasshopper II (courtesy Lord Corporation), with the same paint scheme of colored stripes as the original car, but numbered RNDX 166 instead of RNDX 163. Some of the bolt heads near the ends of the car sides reflect the assembly process. You can click on this image to enlarge it and see some of the end sheet configuration.

The Glasshopper experiments seem to have worked all right technically, and showed good durability and corrosion resistance. But they were more expensive to construct and harder to repair than conventional cars, with only about a 6 percent advantage in total weight. As far as I know, they were not duplicated. You can read more in a couple of places: D.C. Ruhmann’s paper in the journal Composite Structures, Vol. 27, 1994, pages 207-213; and in the book Reinforced Plastics Handbook, 3rd edition, D.V. Rosato, D.V. Rosato, and J. Murphy, Elsevier, 2004, pages 530-535.
     Modeling either of the Glasshoppers presents some challenges if the car is to be duplicated accurately. The car body had numerous, though minor, differences from the conventional ACF body, and the stripes and lettering of the paint scheme are not available in any commercial decal or dry transfer. I decided to minimize the modeling problems and essentially convert the Athearn ACF car to an approximate representation of an HO Glasshopper II.  Once this decision is made, most effort focuses on the car ends, since they are the most distinctive major difference. The Giasshopper II was also a 3-bay hopper, unlike the original Glasshopper and the Athearn model, which are 4-bay cars.
     As a starting point, I chose the Athearn “Co-op Fertilizer” car, kit No. 1909, because it is white. Ordinarily I prefer to work on an undecorated body, but since the final base color of the Glasshopper is white, some of the paint coverage difficulties of white paint over black plastic can be avoided by using Athearn’s paint as a base coat Unfortunately, little of the Athearn lettering can be salvaged. I used only the “Caution” notice at the center of the side sill and the dimensional data (these were later covered with tape when overspraying the completed model with white).
     The underframe modification is simple. The end hoppers on the Athearn car are in very nearly the correct location, so the modification is to replace the two center hoppers with a single one. The Athearn model has flat (horizontal) “floor” segments between each hopper. I sawed through the center of each of these, then used styrene cement to attach the two frame ends and one of the hoppers to a piece of 0.040 styrene sheet, about 30 scale feet long, for stiffness. The Athearn weight attaches to pins on the underframe, and can be used as a spacer to maintain the correct final length of the modified frame. The outlet gates on the Glasshopper were horizontal sliders, more like the ones on the Athearn Pullman-Standard (ribbed side) car than the ACF model, but I chose to ignore this detail. If you choose the model the original Glasshopper, you need make no underframe changes (again, except outlet gates).
     The ends, as mentioned, are distinctive, and were essentially the same on both Glasshoppers. Here is how I modified the Athearn slope sheet/end part to resemble the Glasshopper end. The Glasshopper had a smooth slope sheet except for a horizontal angle, and the end below the slope sheet had deep, formed ribs running vertically. The large diagonal stiffeners on the Athearn end accordingly were removed. There is also a small horizontal rib on the Athearn slope sheet; this was retained, and a piece of 0.020-inch styrene, 6 scale inches wide and as long as the end width, was glued on edge along that rib to represent the Glasshopper’s horizontal angle. 
     The photo below shows the stock Athearn end (lettered for Athearn’s version of the Glasshopper I, discussed below). You can see the large diagonal stiffeners which had to be removed.

     The Athearn  lower end sheet, the vertical part, was turned into the five ribs of the Glasshopper by dividing the end horizontally into eleven parts, marking parallel vertical lines, and razor-sawing along each of the lines up to the slope sheet. Then every other sawed strip was removed, starting at either edge, so that five ribs remained. The center one lies across the hole in the original end sheet, and to make it full length, one of the removed strips was fitted. Now a piece of 0.020-inch styrene was glued behind the ribs, so that when the slope sheet/end piece is in place, the face of the ribs will be flush with the edge of the cut-out in the car side, as on the prototype. At this point, I installed (but didn’t glue) the slope sheet/end part into the body. The Glasshopper end also has lighter diagonal angles flush with the plane of the end ladders. I modeled these with 1/16-inch Plastruct angles, cut to fit, and added small gussets from 0.010-inch styrene sheet.
     Here is an angled end view of the completed model, to illustrate the work on the ends, though it would have been better to photograph the modified end piece before inserting it into the car body.

     The car side can be made to resemble the Glasshopper II by removing the narrow rib of the Athearn car side, about two-thirds of the way up the side, and by filing the “overhang” at the top of the car side so it is vertical rather than overhanging. If you wish to model the original Glasshopper, the sides curved smoothly onto the top, with about a 2-foot (scale) radius; the Athearn body has enough material to permit filing to this contour. 
     Lastly, the “trough” hatches were added. These hatches do not duplicate the fiberglass hatches on the Glasshopper, which had ribs running across the hatch rather than the lengthwise ribs on the Athearn hatches, but the general appearance was acceptable to me. 
     The model car resulting from this work is only an approximation to the Glasshopper, not only because there are several detail differences remaining, but also because the Athearn car is not as tall as the Glasshopper. To remedy the height would be a larger project than I was interested in.
     Turning now to finishing, I assembled the underframe to the body, carefully locating the slope sheet/ends with the underframe tabs, and used modeler’s putty to fill the gap where the top of the slope sheet meets the body. This would also be the time to fill any other gaps or gouges from construction work. I also added a Walthers white metal Ajax brake wheel. Several light coats of Floquil Reefer White were sprayed on until the color was uniform. This was given several days to dry thoroughly before starting work on the stripes. 
     Using the prototype photos as a guide, drafting tape (not masking tape) was cut into strips 3 scale inches wide to define the gaps between the stripes. These were then applied with 9 inch separations for the stripe width. These were pressed down firmly, along with tape to cover the rest of the body. Additional pieces of tape were prepared with low stickiness or “tack” by applying and removing them several times to the sheet of glass I use for cutting. These covered the stripes not being painted at any one time.
     The stripe colors require some mixing. Choosing the exact color is difficult because the photos of the prototype Glasshoppers differ considerably in color rendition with the lighting conditions. Accordingly, I felt that an exact match was neither necessary nor very practical. The upper stripe was mixed from Boxcar Red with a few drops of Roof Brown; the second stripe was painted with straight Pullman Green; the third stripe was mixed from Reefer Orange with several drops of Black; and the bottom stripe was mixed from Foundation with several drops each of Roof Brown and Black. 
     I painted all of these Floquil colors with light spray coats, in one painting session, by allowing about 15 minutes between colors for drying (while I was mixing the next color) and occasional using of a hair dryer to speed the process. I had no trouble with covering the prior stripes with the low-tack tape, but if it sounds risky to you, you could spread the process over two or more sessions.
     The “Plate C” label and the small lettering on sides and ends was taken from a Walthers modern covered hopper decal set, No. D561. Some of the capacity data was pieced together, since I decided to reproduce all the correct numbers in that group. These are:

CAPY 200 000 LO
LD LMT 208 800
LT WT 54 200 NEW 4-83

On the side sill under this lettering is the legend, “1 1/2 IN HF COMP SHOE” (this can be pieced from the Walthers set; it refers to the 1.5-inch-high friction composition brake shoes). This also appears at the other end of the car, beyond the “lube plates.” My lube plates were taken from a Herald King set remnant I had on hand; they are available from several decal makers.
     The remaining lettering comprises the reporting marks and number, the Cargill-SP-ACF logo, and the large Glasshopper II name. Since no commercial products are close to these items, all were made as dry transfers. Artwork was made for these by tracing from an enlargement of a prototype photograph, then having the transfers made commercially by the 3M “Image-N-Transfer” process (this process was later sold to Letraset; I understand there are still graphic arts suppliers who do custom transfers this way). I have the lettering artwork available and would be happy to make it available to anyone who wants to make decals or dry transfers.
     After applying these transfers, the car was oversprayed with Testor’s Dullcote. The prototype is actually rather glossy, as a polyurethane coating was applied to the exterior, but HO scale models with high gloss simply do not look realistic. I finished the car with a bit of Grimy Black on trucks, since the car is modeled in its nearly-new condition. Here is how it looked (the photo is a little washed out):  

Unfortunately, I no longer have this model. It was part of the Lord layout project, and went with the layout on its travels. I’ve never learned what was the final disposition of that display layout, or of its structures and rolling stock. 
     Athearn has done a commercial lettering version of the original Glasshopper by simply putting the lettering on their standard ACF Center-Flow car. The ends are unmodified, but the appearance in a side view is good, and the car does have the correct four bays of the first Glasshopper. Here is a side view:

The stripe colors here seem deeper than what I modeled, and deeper than the prototype photos I have, but do represent the general appearance well.
     Although this prototype is well beyond my own modeling era, it was an interesting challenge to research and build, and after all, this car does have a Southern Pacific connection!
Tony Thompson

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