ACF also made a 4650cf 3-bay version of their covered hopper car that was the same height and width as the 5250cf 4-bay car but several feet shorter in length. The Atlas ACF model is a very nice model of the shorter (in length) 4650cf car (and the old Front Range and McKean ACF covered hoppers were models of the ACF 4650cf car as well). Description: A mega pack of 18 photo textured ACF Hoppers. Included in this pack is skins for ACFX (3), ADMX (3), AEX, ATSF (3), BNSF (2), CCLX (2), CSXT (4) and SP. Models is courtesy of Jointedrail, and was reskinned by Matt Reeves (epa).
Overview
It is hard to trace the earliest covered hoppers, as the idea of roofing an open top, even with just a tarp, isn't that radical. On the other hand, since self-clearing hoppers really only go back to the 1890's, covered hoppers can't go back much further. (Around 1903, the B&O showed a hopper-box car, with a fold-up floor to covert from flat-bottomed box car or sloped floor hopper.) In 1911, ACF built a covered hopper for Anheuser-Busch.
But it took the development of welding to make covered hoppers practical, on the eve of WWII. It also took the idea of mechanical handling of powders to make such cars useful. (Imagine your growing family requires more and more groceries. You buy flour and sugar in sacks, but as the demand grows, you can get these in bulk. But first of all, you'll told you would have to unload the family car by letting the material flow out UNDERNEATH the car, so you would have to equip the garage with a conveyor system. And since this would contaminate the vehicle, you'd have to buy another auto just for this use. This only becomes inefficient if you have a REALLY BIG family.)
The first covered hoppers were behemoth cars rated at only 40 tons, for carrying carbon black powders and small cars for cement. In the '50's, the use of covered hoppers for other commodities gradually assumed importance. It took the acceptance of the 100 ton truck late in the '50's that really got things going, but even so, it was very long before grain shipments shifted from box car to covered hopper.
The commodities shipped in covered hoppers was so dense the designers didn't try to get a little extra volume by going to an offset design as with open-top hoppers, so the ribs were always on the outside. Generally there were an extra pair of ribs, making the 10 panel covered hopper the standard while open top (twin) hoppers opted for 8 panels. The PS-2, Pullman's attempt at a standard plan, had an internal partition, and in this location, left off the stiffening rib on the outside, giving the characteristic rib spacing of the Pullman design (both twin and three bay).
Following the acceptance of the frameless tank car in the early '60's, covered hoppers also followed. These cylindrical or tear-drop shaped cars could have their bottom outlets along the center line of the car, since there was no center sill to interfere. Thus arose the ACF Center Flow and others of type.
Post-steam modelers have a lot of designs to refer to (by comparison to the paltry few designs available c. 1950). For one thing, back in steam days, of the available truck capacities (40, 50, and 70 ton), almost all covered hoppers used 70 ton trucks. Modern modelers have 70 and 100 ton truck versions.
Then there is plate clearances. In steam days, there was only Plate B cars. Modern prototypes can be built to taller clearances, Plate C, etc. Thus for a similar capacity, a car could be long but not as high, or higher and shorter.
Finally, as time went on, the designs evolved. Pullman in particular kept calling their covered hopper a PS-2, even as the design underwent radical changes. In '62, they raised the center sill inside the outlet hoppers, thus allowing the car to discharge in the center of the tracks. This center discharge feature is one of the main advantages of the ACF Center Flow, so Pullman called these cars 'CD' (which is easy to confuse with ACF's 'CF' designation).
For some ACF builder's photos of covered hoppers click here.
Acf Hoppers
Rebuilt Covered Hoppers
- At first, covered hoppers were not designed as such, but merely converted from existing freight cars, often from cars otherwise near the end of their revenue life. As you can image, many strange examples were seen.
ACF 1,958 Cubic Capacity Cars
- ACF was not the only builder to use this design, so there are some subtle differences from car builder to car builder, as well as several options from ACF. Still, this was a very standard design that dominated the tiny fraction of steam-era covered hoppers.
PS-2's
- Two-Bay - First units built in '54, and several models have appeared, including Model Die Castings and Atlas.
- Three-Bay - This is basically a 50% bigger two bay, produced during the same timeframe as the two-bay from the early '50's into the early '60's. The capacity was 2,893 at first, but raised to 3,215 in '58 by raising the sides four or five inches. In terms of modeling, the two are pretty close. In '60, again an increase, to 3,500 cubic capacity, but this was done by raising the sides 12 to 14 inches, so it is harder to overlook.
AHM made a model of the 2,893 cubic capacity car, and the dies passed to Con-Cor. Due to the later Center Discharge Pullman cars, the model designation of this car has been retrofitted with the 'SD' (side discharge) designation, although during the time they were built, this wasn't used, this being the only version.
Specifically, the model has the post-'57 all hat-section rib sides, as the first version had a channel rib over each truck bolster. - CD4,427 - Prototype produced from early '64 and on, with over 19,300 cars produced. It has the 'missing rib' feature that I look for to spot PS-2's. This kit is made by Walthers. It is easy to confuse this with the Con-Cor model (at least I did), but the date of construction and 'CD' description should be a way to identify it. Another spotting feature is that the earlier PS-2 has an overhanging roof, 'T' section type ribs and some rivets on the flanges of the ribs.
Acf Covered Hoppers
Con-Cor/Walthers kit side-by-side comparison for both length and height
- CD4,740 - built from 1966 through '71. It has a nearly flat roof, 17 panel sides, and is Athearn's '54-foot covered hopper'. The 4,740 and 4,750 designs are often mistaken for each other, although the 4,750 has two more panels. Plans and a complete roster by Eric Neubauer appeared in the Oct. '93 Railroad Model Craftsman.
- CD4,750 - built from 1972 through the 1990's at least. It is one of the most common freight cars in the rail scene since the late '70's. It has a 19 panel side with a raised trough and compound curve roof (called by some a clerestory roof). InterMountain's kit is based on a particular 1978 order built for the Soo and plans of this appeared in the Dec. '83 Mainline Modeler.
Center Flows
- CF4600 Three-Bay Car - produced from 1965 to '81, with over 15,000 cars built. It is a Plate B car, lower and henceforth longer than the CF4650. Made by Accurail.
- CF4650 Three-Bay Car - produced from 1964 on. A Plate C car. McKean and now Atlas have models of this car. Addition of a large stiffening rib along the top makes a visual difference.
- CF5240 Four-Bay Car - produced from 1964 until '82, based on Plate C clearances. Produced by Athearn, Bachmann, and Tyco. (These models were often cut down to three bays to model the 4650.)
Airslides
- The two-bay was introduced in 1953, and numerous models have appeared, including ECW, Walthers, Con-Cor. Steve Wagner said: 'I've built two of the old E&B Valley (now ECW) Airslides, at least two of the Walthers single-bay ones, and at least two of Con-Cor's. The E&B's were fairly tough to get together, as you've noted. The Walthers kits I built had the END bracing cast in place, but the four slanted braces had to be cut both to length and at an angle at each end, which is a bit tricky. The roof may also need work to get it to fit right. The Con-Cor kit for the early style car have ALL the braces, including the slanted ones, cast integrally with the body, which must have been one of the best casting jobs since Benvenuto Cellini did his Perseus with the head of Medusa.
'That one really is a great kit, and it's my favorite Con-Cor product by a considerable margin. Con-Cor also has a kit for the newer style Airslide, without the four troublesome braces - The larger version is only produced by Walthers.
HO-Scale ACF 70-ton Open Side Hoppers - KATO USA : Precision ...
FMC Cars
See Full List On Rapidotrains.com
- 4700 - Built from 1971 to 1981, with some 6,825 cars produced. It has 17 panel sides, but the sides distinctively extend down lower than the PS 'high rise' design. Modeled by MDC.
Tank Cars
To start with, there are two basic considerations. First of all is the size. Generally it is given in gallons. During the late steam-era, the average size was 8,000 gallons, with perhaps an equal distribution of 7,000 and 10,000 gallon tanks. The smallest would be 3,000 or 4,000. In about 1953, the CP introduced the largest size up until then, 19,000 gallons.
But not all 8,000 gallon tank cars were the same in overall dimensions. A tank could be short but fat, or long and thin. In general, older tanks were smaller in diameter for a given gallonage.
The other consideration was type. Most tank cars carried petroleum, and for these and other relatively harmless liquids, the car was just a steel cylinder, with an expansion dome on top. The size of the dome was related to the size of the tank, which is a problem of some older kits.
Some cars were insulated, either to keep the contents warm (such as Baker's liquid chocolate cars or cars carrying tar), or cool, to prevent evaporation. These cars can be identified by the recessed ends, as the insulating wrapper projects a slight bit past the end.
Some cars had to be pressurized. These either carried extremely volatile liquids like propane, or dangerous chemicals, that can't be allowed to vent to the atmosphere. These cars had a small housing (also called a dome by modelers) on top for the pressure vents, etc. Pressurized tank cars were insulated. The insulation is needed to keep the pressure from rising too high in hot weather.
In the early 1900's, there was a frameless tank car design which was introduced and several hundred cars built. But the railroads were skeptical, and shortly therefore it was decreed that any cars built after a certain date (if memory serves right, 1917) had to have an underframe. (The frameless cars were grandfathered in, and a few survived until the early '50's.)
In the early '60's, the idea was re-introduced, and this time, caught on. The idea was that a tube is pretty strong by itself (as witness an airplane). The idea also spread to frameless tubular shaped covered hoppers.