THE AMERICAN SOCIETY of MECHANICAL ENGINEERS

ASSOCIATION OF

AMERICAN RAILROADS

R A I L R O A D W H E E L

D Y N A M O M E T E R

CHICAGO TECHNICAL CENTER

91 st NATIONAL HISTORIC MECHANICAL

ENGINEERING LANDMARK

Nov. 29, 1988

AMERICAN SOCIETY OF MECHANICAL ENGINEERS

RAIL TRANSPORTATION DIVISION

CHICAGO SECTION, REGION VI

NATIONAL HISTORIC MECHANICAL ENGINEERING LANDMARKRAILROAD WHEEL DYNAMOMETER

ASSOCIATION OF AMERICAN RAILROADS1955

THIS INERTIA DYNAMOMETER TESTS RAILROADW H E E L S U N D E R C O N T R O L L E D C O N D I T I O N SEXCEEDING NORMAL SERVICE: (A) MAXIMUM BRAKESHOE FORCE OF 40,000 POUNDS; (B) SPEEDS UP TO178 MPH; (C) THE LARGEST EQUIVALENT INERTIAWHEEL LOAD IN RAILROAD PRACTICE OF 127,000POUNDS; (D) SIMULTANEOUSLY APPLYING LATERALAND VERTICAL LOADS OF 15,000 POUNDS AND 60,000POUNDS, RESPECTIVELY (A UNIQUE CAPABILITY).SPECIFICATION: JOSEPH M. WANDRISCO (US STEEL);DESIGN AND CONSTRUCTION SUPERVISION: REX C.SEANOR (ADAMSON UNITED). IN 1983 IT WAS MOVEDFROM US STEEL TO THE AAR. COMPUTER CONTROLADDED IN 1987.

INTRODUCTION

The railroad wheel supports the car or locomotiveas it rolls on its tread along the rail and guides thevehicle through curves and switches with its flangewhich projects outward from the tread. The cast orwrought steel wheel also acts as a brake drum. Whenbrakes are applied, the brake shoes press against thewheel tread, and through their rubbing friction slowdown, stop, or control train speed. As running speedsand weights on wheels doubled and redoubled in thelater part of the 19th century, the combination ofmechanical and thermal stresses often caused cracks todevelop in the cast iron wheels. Some of the cracksled to loss of large chunks of wheel material anddisastrous wheel failures (train wrecks).

About 100 years ago, railway mechanical engineersand metallurgists began formal investigation of castiron wheel failures, and of wheel and brake shoedesign, materials and manufacture. This resulted indevelopment of dynamometers so full-sized wheels andbrake shoes could be tested under controlledconditions to improve service performance and enhancerailroad safety.

Prior to the use of dynamometers, only a drop testwas used to determine the resistance to fracture ofcast iron wheels. However, the drop test did notadequately predict performance in grade braking (Ref.1).

EARLIEST WHEEL AND SHOE DYNAMOMETERS

On the Southern Pacific Railroad, every route intoCalifornia involves continuous heavy grade-braking for20 to as long as 85 miles, as from the Sierra summitat Norden down to Roseville. To identify and cull outinadequate wheel designs and manufacture, SouthernPacific designed and built the first known full-scalewheel and braking dynamometer in 1891. A descriptionof this machine and many test results appeared in the1892 Master Car Builders’ Association (MCB)Proceedings (Ref. 1).

Figure 1 shows a full wheel set, two wheelsmounted on an axle, resting on track or drive wheelspowered by a Corliss steam engine. An adjustablespring force beam loaded each journal, a brake beamwith cast or wrought iron brake shoes applied brakingforces to both test wheels, a scale beam measuredretarding forces, and a brake cylinder and lever gavetypical braking ratios and forces on freight andpassenger car wheels of the day. Starting with 10psi, brake cylinder pressure was increased 5 psi eachfive minutes through 50 or more psi. At 30 mph, up to100 braking hp per wheel was generated which crackedany but the best chilled iron wheels. Continueddifficulties in the next decade or so led SouthernPacific to start using all-steel wheels (wrought steelat the time).

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THE STEEL REVOLUTION: LONGER HEAVIER CARS & TRAINS.

capacity freight cars became common as all wood carsquickly disappeared. In passenger service, the moveto stronger and safer all-steel cars became a realitybefore 1910. Two results of the MCB 50-car train airbrake tests of 1886-7 were the conversion to thequick-action automatic air-brake starting in 1889 andthe invention of the energy-absorbing friction draftgear. These three developments permitted longer andheavier freight trains to boost railroad capacityduring the 1905 - 1925 era.

over in freight car construction and 40- and 50-tonThe years from 1895-1905 saw steel rapidly take

As car weights increased, heat input to the wheeltreads increased. Higher operating speeds with morepowerful locomotives increased the braking heat duringstopping by the square of the speeds. These factorsplaced even further demands on the integrity of thewheels.

Several other dynamometers were built toinvestigate braking and its effect on shoes andwheels. American Brake Shoe and Foundry Co. designedand started operating the first of severaldynamometers at their Mahwah, NJ, works in 1908 tostudy the effects of increased braking loads. TheMahwah dynamometer was used for detailed analyses ofthe several types of shoes used in thePennsylvania-Westinghouse steel passenger-train testsof 1913 (Ref. 6). These tests brought together animproved Universal Control Valve with anelectro-pneumatic option, and clasp-brake rigging (twoshoes/wheel) with 150 percent braking ratio at 100psi (1.5 x car weight). This system enabled a 1200-ftemergency stop from 60 mph with twelve 6l-ton steelcars and a 200-ton 4-6-2 K2s steam locomotive andtender. Around 1910, the University of Illinoisconstructed a braking dynamometer. As nearly as canbe determined, the Pennsylvania RR designed and builta brake-shoe and wheel testing machine about the timeof WWI.

Although the quality of chilled cast iron wheelsimproved through the research of the Association ofChilled Car Wheel Manufacturers, steel steadily tookover for passenger and locomotive wheels. Passengercar weights steadily increased to the 90-ton rangethrough the 1920s and into the 1930s when mechanicalair conditioning was added. Locomotive tenderssimilarly began their growth to truly mammoth sizewhich required wrought steel wheels.

Figure 1. Southern Pacific RR 1891 Full Wheel SetDynamometer.

In 1893, the MCB Association, forerunner of theMechanical Division of the Association of AmericanRailroads (AAR), determined that a full-scale brakeshoe testing machine was essential to establish anindustry-wide standard for friction and wear of themany makes of brake shoes in use (Ref. 2-4). Withassistance from the Pennsylvania Railroad (PRR),George Westinghouse (later ASME President) and WilliamA. Sellers Co., the brake shoe testing machine inFigure 2 was manufactured in the PRR shops andassembled in Westinghouse Air Brake’s plant inWilmerding, PA. Here the new machine and itsdynamometer were put through exhaustive initial andoperating tests. At the time, "dynamometer" referredonly to the mechanical force measuring apparatus,which along with speed, time and distance we nowinclude in the term "instrumentation". In 1900, theMCB testing machine was transferred to PurdueUniversity in West Lafayette, IN (Ref. 5) where theofficial MCB tests were continued until the machinewas scrapped in 1942.

Figure 2. Master Car Builders’ (MCB) Brake ShoeTesting Machine Designed 1893.

Elevation. Section Showing Jaw-type Clutch.

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THE DAWN OF A NEW AGE: DIESEL-ELECTRIC STREAMLINERS

1933 and 1934 saw the light-weight diesel-electricstreamliners burst upon the scene with Union Pacific’saluminum "City of Salina" and the Chicago, Burlingtonand Quincy’s stainless steel "Pioneer Zephyr". Lightweight, high speeds, air-conditioned comfort andmodern design were the watchwords in helping railroadsregain many passengers lost to the automobile in thelate ’20s and early ’30s. After covering the 1070 oddmiles from Denver to Chicago at over 77 mph average,and running long distances at 90 and 100+ mph, the"Pioneer Zephyr" was proudly displayed at the ChicagoWorld’s Fair. This first Zephyr and its 600-hpGeneral Motors 201-A two-cycle diesel engine wasASME’s 54th National Landmark in 1980 and is ondisplay at Chicago’s Museum of Science and Industry,some five miles south of the Illinois Institute ofTechnology and the AAR Technical Center.

Many railroaders felt the PRR/WABCO 1913 emergencytrain stop of 1200 ft from 60 mph had become abenchmark. By ratioing the squares of the initialspeeds and adding about 8 percent, the 100 mphstreamliner should stop in about 3600 ft in emergencyon level track. At higher speeds and total shoeforces, cast iron shoe friction decreases. Therefore,speed sensitive brake equipment was developed whichused much higher shoe forces than the then standard150 percent braking ratio. Speed governor controlprovided 250 percent braking ratio from 100+ down to60 mph, 200 percent to 40 mph, 150 percent to 20 mph,then stepping down to 100 percent. This enabled the90-100 mph streamliner with HSC (High Speed Control)to make emergency and full-service stops in a mile orless. However, the instantaneous braking hp per wheelin high speed zones went up into the 500 to 1000 hprange!

By 1947, high speed streamliner service coveredmost of the country. As streamliner service grew, thediesel-electric locomotive expanded into the 2000-2250hp range. Electric multiple-unit control enabledthree or four to be operated from one control stationto provide the 6000 to 8000 tractive hp required forquite long trains of 15-18 streamlined cars.

In the late 1940s, the 6000-7000 hp four-unitdiesel-electric freight locomotives had amplydemonstrated their worth and the full North Americanmotive power revolution was off and running. Within15 years, virtually every railroad in North Americahad changed from steam to diesel-electric. The lastremaining unit of the original 4-unit 5400 hp GeneralMotors "FT" demonstrator with the 567 diesel engine ispreserved at the National Museum of Transport in St.Louis and was ASME’s 77th National Landmark.

WHEEL PROBLEMS FROM HIGH ENERGY TREAD BRAKING

During the late ’40s and early ’50s, increasingnumbers of diesel-electric locomotive wheel failureswere occurring. It became apparent that these wheelswere being thermally overloaded. Wheel manufacturersbegan research to develop new designs and heattreatments. The University of Illinois dynamometerwas used to conduct wheel industry research on thermalcracking and explosive failures. The AAR ChicagoTechnical Center acquired the Pennsylvania RR’s brakeshoe and wheel dynamometer (Ref. 7) in 1955 to examinethermal braking loads with cast iron shoes, Figure 3.These studies led to a more cautious approach tobraking 36-40 in. diameter wheels with 27,000 to

Figure 3. PRR Dynamometer at AAR Chicago 1955 - 1976.

33,000-lb wheel loads. As a consequence, modern 4000+hp diesel reduces units have dynamic/blended brakingwhich reduces the heat input to the locomotivewheels. The AAR dynamometer was scrapped in 1976because of old age.

COMPOSITION BRAKE SHOES

In the 1960s, the high friction composition brakeshoe, consisting of composite friction material bondedto a steel backing plate, became widely accepted.Composition shoes had as their chief advantage two tothree times the kinetic friction on a steel wheel asthat of cast iron brake shoes at medium to highspeeds. Therefore, because much lower shoe forcescould be used to obtain the same stopping ability,brake systems were redesigned and simplified. Theclasp brake rigging with two shoes per wheel, neededwith cast iron shoes, was in most cases replaced witha single composition brake shoe per wheel. Smallerbrake cylinders and associated rigging parts led tolower brake system cost.

THE LANDMARK DYNAMOMETER

U. S. Steel Corp., a major manufacturer of wroughtsteel wheels and axles, created preliminary designspecifications for a railroad wheel and axledynamometer in the early 1950s. USS wantedcapabilities that went beyond those of brakingdynamometers, such as those owned by American BrakeShoe and Foundry Co., American Steel Foundries, ARMCOSteel, The Budd Co., and Westinghouse Air Brake.

The Adamson United Company of Akron, Ohio (now apart of Wean Industries) was contracted by USS in 1954to build the dynamometer for the Applied ResearchLaboratory in Monroeville, PA. Adamson United hadextensive experience in building dynamometers for theautomotive and aircraft tire industries. This machinewas used at USS for nearly three decades to evaluatethe performance of railroad wheels, axles, and brakeshoes (Ref. 8).

In the early 1980s, The Association of AmericanRailroads wanted to acquire a dynamometer to evaluate

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the effects of grade or drag braking parameters androlling loads on residual stress alterations invarious freight-car wheel designs. AAR also needed adynamometer to test composition and metal brake shoesfor certification and quality control purposes.Therefore, AAR purchased the AU/USS dynamometer in1983. The cover and Figure 4 show the machine at theAAR Chicago Technical Center.

This dynamometer has the capacity to test wheelsunder a variety of braking and rolling-contact loadingconditions. Grade, stop, and static braking tests canbe conducted with a high degree of precision. Inaddition, axles can be tested as rotating cantileverbeams (Ref.9).

A modern control and data acquisition system wasinstalled in 1987 to provide automatic test sequencecontrol, automatic speed control, closed-loop servocontrol of brake application, digital display of testinputs and test results, and digital data gathering.

The machine is powered by a 200-hp DC mill motorto speeds ranging from 0 to 1500 rpm (0 to 178 mph fora 40-in. wheel). For reference, maximum domesticfreight and passenger train speeds are 80 and 120 mph,respectively. Up to 450 hp is available duringacceleration or deceleration. The power supply forthe motor is a 250 kW generator with an adjustablevoltage regulator with current limit. The generatoris driven by a 400-hp synchronous motor.

Ten thick and four thin 64-inch-diameter steelflywheel disks can be bolted to the flanged rotorshaft to produce the inertia effect of dynamic wheelloads. Thus, 54 increments of 95 slug-ft² eachprovide inertias ranging from 270 to 5405 slug-ft².This inertia capability is more versatile and largerthan that of any other railroad dynamometer. Theequivalent wheel load capability, which is dependenton wheel diameter, is shown in Table I for severalwheel sizes.

TABLE I.

WheelDia.,Inches

Dynamometer Typical VehicleEquivalent GrossWheel Load, Wheel

Pounds Load,Min Max Type Pounds

28 6,400 127,000 45-Ton-CapacityAuto Rack Car

4,600 92,000 70-Ton-Capacity 27,500Hopper Car

3,900 77,000 100-Ton-Capacity 32,875Tank or Gondola Car

3,500 69,000 125-Ton-Capacity 39,375Covered Hopper Car

3,200 62,000 4-axle 3800 hp 35,000Locomotive

24,375

33

36

38

40

The flanged stub axle, Figure 5, is instrumentedwith strain gages to measure torque during braking.This method of measuring retarding force and hpreplaced the original method of measuring thedifferential output of load cells supporting the brakecylinder torque beam in 1968. Wiring for the torquecell and other strain or temperature sensors is routedthrough the hollow axle to a slip ring mounted on theoutboard bearing.

The test wheel (28 to 46-in diameter) is mountedon the stub axle. The flange is bolted to a flexiblecoupling which is in turn bolted to the inertiashaft. The other end of the stub axle fits in theoutboard bearing. When the rail wheel is used fortests, the outboard bearing is allowed to float topermit vertical loads of up to 60,000 lb to be appliedto the wheel tread with the motor/screw and springload frame.

Figure 4. AAR Dynamometer (former US Steel) fromMotor End.

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Figure 5. Wheel and Strain Gaged Axle with BrakeShoes, Load Cells, and Brake Cylinders.

Braking is provided by two single-shoe systems.One system, consisting of brake cylinder, load cell,brake head, and brake shoe, has a shoe-force capacityof 6,500 lb and is used for freight-car wheel, and

cast-iron brake shoes at brake forces of up to 40,000lb per shoe, is also available.

brake shoe tests. The other system has a capacity of13,000 lb and is used for locomotive and passenger-carwheel and brake shoe tests. The servo system permitsconstant torque and constant force tests to beconducted and also allows the torque and force buildup rates to be controlled. The original clasp-typebrake arrangement, suitable for testing locomotive

oscillated laterally at 0.2 to Hz to simulate curvingand lateral instability.

As shown in Figure 6, the replaceablefriction-driven rail is a continuous ring ofheat-treated rail steel and is bolted to a fabricatedwheel. The rail wheel can be loaded laterally (up to15,000 lb) with a hydraulic cylinder and can be

Two grinders are used to maintain proper profilesof the wheel and rail. An armor steel guard protectspersonnel should a test wheel fracture and alsoassists in the collection of dust for hydrostaticcleaning. Cooling for wheel and brake shoe tests isprovided by suction from the air cleaning unit, an8650 cfm fan, or water spray, if desired.

Briefly, the landmark dynamometer is capable ofsubjecting full-size railroad wheels to controlledbrake-shoe forces of up to 13,000 lb with compositionshoes and 40,000 lb with cast iron shoes at speeds upto 178 mph with equivalent inertia wheel loads up to127,000 lb. In addition lateral and vertical contactloads up to 15,000 and 60,000 lb, respectively, can beapplied during braking. These capabilities are inexcess of those required to duplicate serviceconditions on North American railways.

Figure 6. Elevation Drawing Showing Rail Wheel in PitBeneath Machine.

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SUMMARY

During the past century, the use of dynamometersby AAR has been intermittent as various wheel andbrake shoe problems arose and were solved. Thisprogression started in 1894 with the MCB machine atWABCO and then Purdue until the WWII years, resumedwith the PRR machine in Chicago during the 1955-1975period, and continues with the present AU/USS machinein Chicago beginning in 1983. The ability to applylateral and vertical rolling contact loads and thermalbraking loads to the wheel tread with modern controland instrumentation makes this machine unique in therailroad dynamometer field.

REFERENCES

1.

2.

3.

4.

5.

6.

7.

8.

9.

Master Car Builders’ Association Proceedings 1892,Pages 115-131 (Southern Pacific Wheel DynamometerTests).

Master Car Builders’ Association Proceedings 1894,Pages 149-161 (Description of MCB Brake Shoe TestMachine).

Master Car Builders’ Association Proceedings 1895,Pages 131-161 (Tests at WABCO on various types ofshoes and wheels).

Master Car Builders’ Association Proceedings 1901,Pages 99-141 (Tests at Purdue University startingin 1900), Pages 466 and 489 (Brake Shoe FrictionLimits and Adoption as Standard).

Young, G. A., M.E., Head, School of MechanicalEngineering, Purdue University “Purdue Universityand the American Railways,” 1928, Purdue LibraryNo.: Goss 625.0 Ro, 85p.

Pennsylvania-Westinghouse Brake Tests at Absecon,N.J. 1913, copyright 1913 Pennsylvania Railroad,Printed by Westinghouse Air Brake Co.

Research Center Annual Reports of 1956, 1957 and1960, Association of American Railroads, TechnologyCenter, Chicago, 16, IL. (Brake shoe and wheeltests with former Pennsylvania R. R. Dynamometer).

Wandrisco, J. M., and Dewez, F. J., Jr., “Study ofDefects that Originate in the Treads of RailroadWheels During Service,” ASME Paper 60-RR-1,ASME-AIEE Joint Spring Railroad Conference,Pittsburgh, PA., 1960. (Wheel tests at U. S.Steel).

Carpenter, G. F., and Johnson, T. E., “AARDynamometer, “Proceedings of the 1988 JointASME-IEEE Railroad Conference, Pittsburgh, PA,April 13-14, 1988, pages 103-109.

BIOGRAPHICAL SKETCHES

Engineering and also attended Carnegie Institute of

Engineer, Railroad Products, at the Monroeville, PA,

the co-inventor of the highly successful USSCURVEMASTER Rail.

Joseph M. Wandrisco, Mem. ASME, was born and raised inthe Pittsburgh, PA, area. He was graduated from GroveCity College in 1939 with a degree in Chemical

Technology. His career with US Steel started in 1940at the Homestead, PA, works and he joined the ResearchDepartment in 1950. He rose to become Chief Research

Applied Research Laboratory of US Steel, retiring in1979. Mr. Wandrisco was responsible for thefunctional design specifications and successfuloperation of the Landmark dynamometer. He is known as

Rex C. Seanor, Mem. ASME, was Chief Engineer atAdamson United Co. when the Landmark dynamometer wasdesigned and constructed. After obtaining his B.S. inMechanical Engineering at Carnegie Institute ofTechnology in 1931, he began his career at GeneralElectric Co. in Lynn, MA. In 1935 he joined E. W.Bliss Co. in Salem, OH, and designed rolling mills.He joined Adamson United Co. in 1946, was responsiblefor the design of large dynamometers for the aircraftindustry and machinery for the rubber and plasticsindustries, and retired in 1973. He is a formerchairman of the Akron Section of ASME and is a memberof Tau Beta Pi and Pi Tau Sigma.

ACKNOWLEDGMENTS

The Chicago Section and the Rail TransportationDivision of ASME and Region VI gratefully acknowledgethe efforts of all who have contributed and cooperatedin the designation of the Association of AmericanRailroads (AAR) Railroad Wheel Dynamometer as aNational Historic Mechanical Engineering Landmark. Inparticular, we thank the AAR for their aid andassistance in preparing the dynamometer and allowingus to propose it for landmark status. Thanks also areextended to the Illinois Institute of Technology onwhose campus the AAR Chicago Technical Center islocated.

This brochure was written by D. G. Blaine and G. F.Carpenter. Photographs were by John F. Valente,typing by Rita A. Potts, and printing by Ethel M. andRosetta Frazier. Thomas E. Johnson is presentlyresponsible for operation and maintenance of thedynamometer.

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THE HISTORY AND HERITAGE PROGRAM OF ASME

The ASME History and Heritage Program began inSeptember 1971. To implement and achieve its goals,ASME formed a History and Heritage Committee, composedof mechanical engineers, historians of technology, andthe Curator of Mechanical and Civil Engineering at theSmithsonian Institution. The Committee provides apublic service by examining, noting, recording, andacknowledging mechanical engineering achievements ofparticular significance.

The AAR Dynamometer is the 91st National HistoricMechanical Engineering Landmark to be designated.Since the ASME History and Heritage program began, 128Historic Mechanical Engineering Landmarks, fiveMechanical Engineering Heritage Sites, and oneMechanical Engineering Heritage Collection have beenrecognized. Each reflects its influence on society,either in its immediate locale, nationwide, orthroughout the world. A landmark represents aprogressive step in the evolution of mechanicalengineering. Site designations note an event ordevelopment of clear historical importance tomechanical engineers. Collections mark thecontributions of a number of objects with specialsignificance to the historical development ofmechanical engineering.

The ASME History and Heritage program illuminatesour technological heritage and serves to encourage thepreservation of the physical remains of historicallyimportant works. It provides an annotated roster forengineers, students, educators, historians, andtravelers, and helps establish persistent reminders ofdivergent paths of discovery. For furtherinformation, please contact the Public InformationDepartment, The American Society of MechanicalEngineers, 345 East 47th Street, New York, NY 10017,212-705-7740.

THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS

Ernest L. Daman, President

Vjecoslav Pavlic, Vice PresidentRegion VI

C. Dan Mote, Vice PresidentEnvironment & Transportation Group

David L. Belden, Executive Director

Arthur W. Ebeling, DirectorMidwest Regional Office

THE ASME NATIONAL HISTORY & HERITAGE COMMITTEE

Euan F. C. Somerscales, Chairman

Robert M. Vogel, Secretary

Robert M. Gaither

J. Paul Hartman, P.E.

Richard S. Hartenberg, P.E.

J. L. Lee, P.E.

Joseph P. Van Overveen, P.E.

Carron Garvin-DonahueStaff Liaison

THE ASME CHICAGO SECTION

Thomas B. Newcomb, Chairman

David W. Mattoon, Secretary

Kevin Meade, Treasurer

Grant H. Arrasmith, History & Heritage

THE ASME RAIL TRANSPORTATION DIVISION

V. Terrey Hawthorne, P.E., Chairman

Ormond Pendy, Vice Chairman

Thomas Schofield, Secy.-Treasurer

Geoffrey E. Cobden, P.E., History & Heritage

THE ASSOCIATION OF AMERICAN RAILROADS

George H. Way, Vice PresidentResearch & Test

Keith L. Hawthorne, P.E., Asst. V. P.Chicago Technical Center

George F. Carpenter, P.E., Manager,Metallurgy Labs.

David G. Blaine, P.E., CEng., Consultant

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