I translate and show the contents of the dictionary I wrote in Japanese language. Some descriptions are not confident in the reliability. Thank you for your advice.
[cushion underframe] is a mechanism that greatly increases the front-rear stroke of the coupling, and increases the buffering capacity of the coupling device. It is equipped on box cars, reefers, gondolas, flat cars and cabooses that dislike shocks, and is understood for its couplers protruding from the car ends.
There are Sliding Center Sill Cushion (SCSC) and End-of-Car Cushion (EOCC).
In SCSC the Duryea System appeared first in 1927. A sliding sill that connects both ends of the coupler was installed in the center sill of the underframe, and impacts were absorbed by steel coil springs. For cabooses only, friction damping mechanisms were provided. In 1952 - 1955, Pullman-Standard supplied some SCSC cars with laminated rubber instead of steel coil under the name "Pullman-Standard Cushion Underframe". In 1957, Hydra-Cushion, which combines friction and hydrauric, was put into practical use. It was followed by all-hydraulic Keystone Shock Control etc. and SCSC became popular with loading devices. For cabooses it was used until the end of SCSC units in the 1980s. Also it is called CTU = "Cushion Travel Underframe" or COCC = "Center of Car Cushion".
In the latter EOCC, Halliburton Company's FreightMaster, which was developed in 1960(?) is the first. Separate shock absorber units are provided at both ends to perform all damping hydraulically. Whereas SCSC works similarly in pushing buff and pulling draft, EOCC works a lot in buff and a little in draft. Compared to SCSC, although the structure is simple, excellent in maintainability, and lightweight, the initial ones were inferior in performance. P-S's Hydroframe and ACF's Freight-Saver (SCSC also exists) are known, and Keystone also manufactures EOCC. All new cars since the 1980s have adopted EOCC system. The centering spring changed from steel coil springs to gas springs containing inert nitrogen gas. In 1975, the AAR established an interchangeable recomended standard between the EOCC units and standard draft gears. The standard includes the M-921-B for general freight services (pre-load 100,000 pounds, established in 1989) and the M-921-D for auto carriers (pre-load 50,000 pounds, established in 1993).In recent years, EOCCs are often called cushion devices.
The buffer capacity is generally represented by the moving travel stroke of the coupler, which generally takes 10-30 inches for SCSC units and 10, 15 and 18 inches for EOCC units. In later years, did the number of cars with EOCC increase and the traveling stroke shrank(?). See page 698-703 of the Car and Locomotive Cyclopedia 1997, page 28 of the MR Aug. 1967 issue (quoting the figure), page 3 of the Freight Cars Journal no.43 (PDF 4.4MB) , and TransPacific R.R. (Confirmation required / investigation ongoing)
In the 1960s, each railway wrote catchphrase (slogan) on the sides of the freight cars indicating the cushion underframe equipment. But it was rare that they used brands from manufacturers such as "Hydra-Cushion" (SP) or "Shock Control" (ATSF). Unique names were used. This is probably because various products were mixed. "Another Cushioned Load" (ACL), "Cushioned Ride" (GN), "Cushioned Cargo" (L&N), "Super Cushion Service" (SR), "Cushioned Load" (UP) and the like. However, many railroads simply wrote to as "Cushion Underframe", "Cushioned Car" and "Cushion Service". See a model collection.It seems that the reason why the notation was abolished in the 1970s is that standardization of specifications and the spread of equipment have made it impossible to differentiate them.
In models, an O-scale boxcar with a movable mechanism was introduced in the MR Aug. 1967 issue. In 2008 Kadee released HO-scale 50-foot boxcars that replicated the functions of SCSC (see TransPacific R.R.). Walthers, Details West and Moloco sell various detail parts (dummy).
Related terms: [Duryea System] [Pullman-Standard Cushion Underframe] [Hydra-Cushion] [Shock Control] [FreightMaster] [Hydroframe] [Freight-Saver] [Cushion-Pak] [gas spring] [coupler] [draft gear] [loading device]
Kuriu, KotaroKyoto, JAPAN
A useful and nicely done summary. Thank you.
Last year I went through my rolling stock collection and tried to find every example of cars which had cushioned underframe terminology on the side (such as Santa Fe's "Shock Control" phrase), with the idea that I would see if they in fact had extended coupler draft gear (dummy) or if I needed to install an aftermarket extention. I have a lot of the Walthers in bags for example.
Sure enough the majority of cars with cushioned underframe vocabulary on the car sides had standard coupler pockets. A few had extended coupler pockets.
It did occur to me that there would be full extension while a car is being pulled in a train, but not when same car is being pushed into a siding, or is bunched up in a yard with other cars on either end. And the extension would be more on one end than the other for a cushion underframed car which is at the end of a string of cars, such as you'd see at a hump yard bowl.
So the search for greater realism for such cars -- installing an extended coupler pocket -- does mean a certain degree of compromise in realism depending on circumstances. A true working cushion underframe would be the dream solution, but frankly some of the cars I found in my collection or on the shelves would not be worthy of what I expect would be a major expenditure should someone (Rapido?) come out with such a retro-fit.
Particularly if you also like to include coupler lift bars.
Dave Nelson
I'd at least include a couple of paragraphs about how SRI/Stanford researched and then designed the Hydra-Cushion approach. As I recall there are good historical 'engineering-research' studies on this.
[Duryea System] is also called "Duryea cushion underframe". The first sliding cushion underframe for freight cars, developed in 1927 by O.C. Duryea System. The shock was absorbed by a steel coil spring and the stroke was about 7-inch. For cabooses only, friction damping mechanism was added. The figure is for caboose (page 385 of the Car Builders' Cyclopedia 1940). B&O is famous for adoption. Other railroads include B&M, CNJ, C&O, RDG, LV, WM, AT&SF, D&RGW, and the like. After the WW2, Hulson and subsequently Waugh Equipment manufactured and called the "Premium car" with improved performance. Because there was no attenuation, the coil spring was frequently damaged, and the flange of the movable beam was worn. On July 1, 1972, the use of the coupler and sliding sill was banned except for cabooses, as it would cause buckling at the joints. See page 698 of the Car and Locomotive Cyclopedia 1997 edition, US Patent US1974017A, RMC August 1978 issue (Trainorders.com), Steam Era Freight Cars and TransPacific R.R. (Confirmation required)
Dummy underframe model of the B&O M53 boxcar by Weaver
In 1935, B&O adopted it for some lightweight passenger cars. See page 577 of "The American Railroad Passenger Car" by John H. White.
Related term: [cushion underframe]
[Pullman-Standard cushion underframe] is a non-hydraulic cushion underframe, and it is said that Pullman-Standard commercialized the Meyer sliding sill. In 1952. the first two box cars were supplied to WP, used a large-capacity laminated rubber shock absorber in the center sill system (see figure). The improved version was advertised as "C-U car" with snubber. Although samples were purchased by BAR, C&O, Erie, GN, N&W, NYC, PRR, WP, SR, and UP, in 1954 - 1955, their subsequent fate is unknown. See PS-1 lists of the Steam Era freight Cars website, and TransPacific R.R. (In my experience, natural rubber (if so) should swell in a few years... :Under investigation)
Page 302-305 of the "Railway Rolling Stocks -Research Materials-" published in 1957
MDC/Roundhouse's model, the coupler pockets were modified. Notice the "Cushion Underframe" on this 1952 boxcar.
Page 3 of the Trains Dec. 1953 issue
Related terms: [Cushion underframe] [Duryea System] [PS-1]
Deleated post.
[Hydra-Cushion] is a brand name of cushion under frame, one of the sliding center sill cushions (SCSC). In 1954, SP commissioned the Stanford Research Institute (SRI) and William K. MacCurdy of the SRI developed Hydra-Cushion. It was introduced in SP and other railroads from 1957. The traveling stroke was 10-inch (20-inch total?), And damage to the load has been reduced by a factor of 25. It is considered the first to use hydraulic pressure for reduction of impact, although friction for damping was combined with. A vertical cylinder is visible in the center of the under floor.
Details West's model with their Hydra-Cushion Underframe (Walthers stock#235-182)page 694 of the Car Builders' Cyclopedia 1961
page S9-31 of the Car and Locomotive Cyclopedia 1974
It seems that MacCurdy with the rights of Hydra-Cushion later transferred to an affiliate of Evans, a major loading device company, and the company used the system extensively. See Wikipedia (William K. MacCurdy), a booklet created by SP, and the SRI International Archive. Manufactured by Dresser and others.
Evans developed and transitioned to the EOCC "Cushion-Pak" in 1970. The last adoption of Hydra-Cushion on SP cars was in 1978 (? Diversion from existing cars?). Around 1980, EOCC's "Hydra-Cushion II" appeared (TransPacific R.R.).
Parts for the HO scale (dummy) were supplied by Bowser (Cal Scale), Details West and Moloco.page 54 of the MR Nov. 1964 issue
Related terms: [cushion underframe] [Evans] [Cushion-Pak]
[Shock Control] is a brand name for hydraulic cushion underframes developed by Keystone Railway Equipment Company, SCSC and EOCC. AT&SF is known for having the logo on its boxcars. See page 684-685 of the Car Builders' Cyclopedia 1966. Naturally, the same AT&SF cars were not drawn with P-S Hydroframe or ACF Freight-Saver. "Shock Control" appeared in 1958 (TrainBoard.com). "Super Shock Control" (photo) was introduced in 1961 with the introduction of an 18" traveling stroke (trademark applied for US Trade Mark in 1963). See TransPacific R.R., "Santa Fe Box Cars, The Shock Control Era: 1954-1995" by SFRHMS.MDC/Roundhouse's model, the coupler pockets were modified
page 684 - 684 of the Car and Locomotive Cyclopedia 1966
Until 1986, ATSF painted freight cars with cushion underframes in deep red. The relationship between Keystone and ATSF is unknown.
I believe you have the functions of the plates and the sprung cylinder reversed in your definition of Hydra-Cushion. The cylinder is what absorbs the impact forces; the plates provide immediate damping of the motion once the force has been absorbed/balanced in the compression. (And provide controlled release without significant 'overshoot' when the compressing buff shock is over or push is released and the underframe extends back to 'rest' position)
Overmod, thank you for pointing. That's right. The Google translation omitted part of the sentence. I tried to fix that. How about this? Incidentally here is an interesting figure. Maybe this is an experimental Hydra-Cushion, appeared in a Japanese book.Page 307 of the "Railway Rolling Stocks -Research Materials-" published in 1957
"Shock Control" was an exclusive Santa Fe trademark...they used underframe equipment from (primarily)Keystone and Hydra-Cushion, among others
Thank you for your comment, azrail. As you say, "Shock Control" was used only by ATSF. And "Super Shock Control" was registered as a trademark by ATSF. The problem is "Shock Control" without "Super". This is what Keystone uses for advertising, including typefaces. Do you know anything about this?
page 654 of the Car Builders' Cyclopedea 1961
[FreightMaster] is also written as "Freight Master". This is the beginning of End-of-Car cushion and is a brand name of Halliburton Company. Around 1960 It was developed. See the company history, TransPacific R.R. A model of the Hubert's Model Railroad
Page 653 of the Car Builders' Cyclopedia 1961
[Hydroframe] is one of End-of-Car Cushion system developed by the Pullman-Standard around 1960. In addition to Hydroframe-60, there were also -40 and -20. The numbers are attributed to the traveling all stroke (inch). Trademark applications were filed in 1960 and 1964. Athearn's model, the coupler pockets were modified.
Related terms: [cushion underframe] [Pullman-Standard]
[Freight-Saver] is a name of cushion-underframe systems developed by ACF. The end-of-car cushion appeared in the early 1960s, and sliding center sill cushion was added around the 1970s. See page 340 of the "American Car & Foundry Company 1899-1999". Athearn's model, the coupler pockets were modified.
Related terms: [cushion underframe] [American Car & Foundry]
[Cushion-Pak] is a brand of cushion device EOCC developed by Evans in 1970. As a result, the company has switched from Hydra-Cushion system. ScaleTrains' model, as is.
Related terms: [Evans] [Hydra-Cushion] [cushion underframe]
This info is pretty interesting.I wonder how much these hydraulic systems leak after several decades of hard service and so-so maintainence.
The Missouri Pacific built in 1960 and 1961 a block of cars that covered series 96200-96349. Some of the cars had 10" Hydra-Cushion while others had 10" Super Cushion underframes. The Mopac didn't name their cushion device - and they are interesting as they had cars built by one manufacturer and then had installed a cushion device by a competing manufacturer (PS car with ACF Freight-Saver cushioning). Do you know who offered the 10" Super Cushion underframe in 1960-1961? Does the 1961 Car Builders Cyplopedia mention that name? Thanks!
Nate