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Chrysler Railroad Cars, or Mopar Freight Trucks

by Michael Dickens and David Zatz

Through the 1930s, Chrysler made revolutionary advances, many of which were used in the Airflow - hailed by some as the first truly modern car (though styling and GM's "whisper campaign" killed sales.) The company used research, experimentation, and application of physical theories such as Newton's law of centers of percussion to balance weight and find the best location for springs, axles, and mounting points.

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As research director Carl Breer pointed out, cars were one thing, but on trains, passengers still took "a beating" and could not read for very long due to the "jolting and uncontrolled bouncing. ... The entire train was articulated except at the rear end of the locomotive, which to us was getting as far as possible from nature's basic law of the center of percussion."

Carl Breer gave Bob Janeway $50 to buy a train set, put him in charge of a new railroad lab, and told him to see "how much faster and safer the trains would operate if their weight distribution was near to requirements of the law of centers of percussion." They could greatly increase the speed of the rail cars if they cushioned the cars from rail imperfections and the "lateral whipping" motions of the drawbars.

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Walter P. Chrysler, who had started his career in the rail industry, connected Breer to the New York Central's engineer in charge, Paul Kieffer. The Chrysler and NYCRR groups worked together, experimenting on miniatures in a laboratory headed by Robert Janeway and including Bill Vandersly and Perce Best. They found how to avoid "crack the whip" forces by changing weight distribution, and by learning how rail and truck forces entered the cars, developed "self-banking" cars. Breer quoted the president of the famed Pennsylvania Railroad, Martin W. Clement, as saying, "I have seen more engineering in this laboratory than I have in my entire life in the railroad business."

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Tearing down existing trucks (the undercarriage of rail cars, including the wheels, suspension, and car support), the group found that many areas which were supposed to absorb shocks did not, and that there was a great deal of unlubricated metal to metal friction and collision. Lubricating all rubbing surfaces greatly improved the ride, but dust would quickly end that. Adding ball-bearing thrust plates between the bolster and frame were a partial solution; then the lab added thrust links with flexing rubber ends. These and other innovations were patented, then quickly licensed to to passenger train makers rather than being made into standalones. The patents were registered to a separate company, created for that purposes.

The first set of cars improved by these principles were the "Mercury" cars purchased by the NYCRR, which:

  • Used lower leaf-spring rates and added spring covers to keep lubrication free from dirt
  • Used high-finish bolster pressure plates, which were kept lubricated
  • Lowered the diaphragm and buffer pressure between cars, and kept their rubbing surfaces lubricated
  • Added thrust links on the trucks (this was a later addition)

The Mercury trains were faster than other New York Central trains, but were more comfortable. They progressed further to a set of lightweight steel side member trucks for New York Central cars, which ran with "a far better ride" for over 100,000 miles. The mighty Pennsylvania Railroad then got involved, running a test train at speeds of over 100 mph, though that test brought some high-speed problems to light. (These issues were later fixed by T.V. Buckwalter of Associated Railroads.)

In 1942, Janeway filed a patent which had the truck frame suspended on swing links, with a single set up springs and reduced unsprung weight, the idea being to insulate the train car from vibration. In 1943 he went further, splitting the truck (which was functionally a single unit in the standard designs) into two components, separating the wheels and axles from the side frames, and mounting the car support on springs, providing a free vertical motion, restricted only by the springs. Lateral movement in any direction was permitted, but restrained by compression and tensile forces. This eliminated rubbing between the parts, and prevented "attendant joltings and progressive wear of the parts."

In 1945, Breer and Janeway jointly filed for a "torsionally neutralized" passenger-car railway truck. The 1945 Breer and Janeway patent eliminated the intermediate mass between the truck bolster and plank and the car body, and dealt with the resulting issues. This design prevented oscillation and secondary effects. By this time, they had a full sized test train, using vertical and lateral accelerometers, and observed truck action through windows in the train floor.

The company moved on to freight cars; there was a shortage of these at the time, exacerbated both by wartime demands and by the inability of freight cars to be driven at high speeds. Increasing the speed of the cars by raising spring rates caused damage to the cars and their contents. Chrysler stopped licensing its improvements piecemeal, and in 1950, they publicly launched a series of freight trucks under their own name, created for high-speed freight cars:

... freight cars equipped with Chrysler Design truck can carry any load, up to full capacity, at passenger train speeds, with full protection from rail originated shocks. ... Several years of hard-accelerated service on some of the largest railroads have demonstrated its endurance and dependability, reduced wear, and lower maintenance costs.
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Tests after 44,763 road miles showed that the average total wear of all the load-carrying surfaces was around 0.039 inches.

With these trucks:

  • Lateral shocks were absorbed by the pendulum-action of the swinger hanger suspension system.
  • Vertical shocks were cushioned by self-contained snubbers and long travel standard Association of American Railroads coil (3 11/16") springs - the softest springs that could be used "within the limitations of coupler height variations under load." Testing showed the snubber lining was only 9% of its initial thickness after the "lab life test equivalent" of 655,000 miles.
  • The stiffness of the cast plank and swing hanger assembly, and absence of free play, inherently helped keep the truck square.

Maintenance was low, according to the company, and wheel changes were quick, using just "a jack, wood blocks, and a crowbar." It interchanged with existing trucks in freight cars constructed to A.A.R. standards, and used standard A.A.R. coil springs, journal boxes, and brake rigging, to make upgrading existing cars practical and to ease maintenance and repair.

The trucks were built, under license, by railroad makers Symington-Gould (Depew, New York); the friction snubber, a significant element, was made under license by Houdaille-Hershey (Buffalo, New York). They did not catch on: Carl Breer wrote, "We had equipped some 1,500 or 2,000 [railroad] cars with these Chrysler railroad trucks which were manufactured by Symington-Gould on a royalty basis." They did, however, appear to continue production after Breer left the company; the FR-5, at least, was produced in 1957 and likely later.

Rolling stock Transport Railroad car Vehicle Train

The Chrysler Design Railroad Freight Truck with Balanced Suspension was standard in General American-Evans "Damage Free" box cars. General American-Evans claimed lower cargo damage, and 50% higher capacity. Two series were made, in 1950 and 1955, and distributed on 25-year leases. The Chrysler FR-5 trucks looked like normal AAR trucks, with shock absorbers (snubbers) added. They weighed 7,700 pounds for a complete truck, with single wear wheels and brake rigging.

Numerous railroads used these dark green GAEX cars, rebuilt and repainted as they were returned from lease; each individual railroad's logos and reporting marks were painted on. The Pennsylvania Railroad still owned or leased around 138 of the cars in 1968, keeping them dark green rather than the Pennsylvania's usual dark red. In 1974, when the 25 year leases were up, General American rebuilt 65 cars with the insignia GAEX 74000-74064, then resold them; they were put back into active service. The fate of the other cars is unknown.

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Testimonials were sent by shippers who used GAEX (General American-Evans) freight cars equipped with the trucks, incuding:

  • ... Better than 60,000 pounds of paint was loaded in the car, which moved through to destination, with damage to only one-quart can of paint. ... It would seem that the handling of paint in the Evans car would eliminate claims almost 100%, enabling the carrier to obtain the full revenue for the handling of the car.
  • ... The total weight of the load was 91,577 pounds ... not even a single box moved a fraction of an inch out of its place. .
  • ... Our usual shipments of bottled goods consist of 50,000 pound loads and average damage loss is 360 bottles per shipment. The GAEX car takes loads of 100,000 pounds and average damage loss per shipment amounts to 3 bottles.

Other cars that used the Chrysler Design Trucks for freight were the Pennsylvania Railroad Merchandise Service box cars, New York Central "Pacemaker" box cars, B&M mail cars, B&O Express freight cars, UP stock cars, ATSF Express cars, Fruit Growers' Express refrigerator cars, and C&O gondola cars.

How the Chrysler Design Railroad Truck worked

The following is from the press release issued by Chrysler:

The freight car body is suspended on U-shaped swing hangers, which act like pendulums. The swinging action of the hangers allows the trucks to move sideways relative to the car body, absorbing the lateral shocks from the rails before they can reach the car body and the lading. The smooth, shock-absorbing effectiveness of the swing hangers is independent of load -- therefore, the fully loaded freight car is protected to the same extent as a lightly loaded freight car.

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The stability of the side frames is assured regardless of the lateral displacement. Any unsquaring tendency of the side frames is resisted by the torsional stiffness of the horizontal portions of the U-shaped swing hangers supporting the spring plank. Because there is no free-play in the hanger mountings or between the plank and hangers, the side frames are effectively held in square alignment.

The cushioning of vertical impacts is obtained by low rate, long travel, standard A.A.R. (Association of American Railroads) coil spring groups. Self-contained, constant-friction snubbers of the expanding shoe type control the coil spring action. The snubbers are mounted on the outside top: The wide spacing, which is the maximum allowed within A.A.R. clearance limitations, imposes the greatest possible frictional resistance to car body roll.


The snubber connections consist of forged rockers preloaded by rubber compression blocks. The assembled rubber compression blocks and rocker connections maintain solid contact in overcoming snubber friction. This construction was developed to avoid uncontrolled vertical vibrations of the car body. At the same time, the connections allow the necessary universal-joint action to accommodate the relative movements between the bolsters and the cast steel spring plank.
Although Chrysler made major contributions to the railroad industry, there appears to be little acknowledgement of their role, including in thier own annual reports.

Bill Sample wrote: I first noticed Chrysler designed freight car trucks under U.S. Army boxcars that dated from the early 1950s. They likely hauled many different cargoes, including explosives, and some are used on military bases. The railroad museum that I am involved with purchased two former milk cars from the Boston & Maine Railroad with these trucks. They were the last ever built for milk car service, constructed in 1957 and 1958, and were designed to be used on passenger trains, which generally ran at higher speeds than freight trains.

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