Brake System Design Optimization Volume L a Survey and Assessment
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REPORT NO. FRA/ORD-78/20, I BRAKE SYSTEM DESIGN OPTIMIZATION Volume I: A Survey and Assessment L.L. Eshelman C.C. Shelleman J.P. Henderson A.T. Kearney, Inc. 100 South Wacker Drive Chicago IL 60606 JUNE 1978 FINAL REPORT DOCUMENT IS AVAILABLE TO THE U.S. PUBLIC THROUGH THE NATIONAL TECHNICAL INFORMATION SERVICE, SPRINGFIELD, VIRGINIA 22161 Prepared for U.S. DEPARTMENT OF TRANSPORTATION FEDERAL RAILROAD ADMINISTRATION Office of Research and Development Washington DC 20590 05 - Braking Systems NOTICE This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Govern ment assumes no liability for its contents or use thereof. NOTICE The United States Government does not endorse pro ducts or manufacturers. Trade or manufacturers' names appear herein solely because they are con sid~red essential to the object of this report. Technical Report Documentation Page 1. Report No. 2. Govemment Accession No. 3. Recipient's Catalog No. FRA/ORD-78/20, I 4. Title and Subtitle 5. Report Date June 1978 BRAKF. SYSTEM DESIGN OPTIMIZATION 6. Performing Orgonizotion Code Volume I: A Survey and Assessment 1--::----,...,.---------------------------i B. ~erlorming Organization Report No. 7. Author's)L.L. Eshelman, C.C. Shelleman, DOT-TSC-FRA-78-1, I J.P. · Hen<;Ierson · · 1\ , 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) A. T. Kearney, Inc.* RR816/R8317 100 South Wacker Drive 11. Contract or Grant No. Chicago IL 60606 DOT-TSC-1040 13. Type of Report and Period Covered ~------------------------------------------------~12. Sponsoring Agency Name and Address Final Report U.S. Department of Transportation Federal Railroad Administration April 1977 to March 1978 Office of Research and Development 14. Sponsoring Agency Code Washington DC ~2~0~5~9~0~------------------------L------------------------ 15. Supplementary Notes *Under contract to: U.S. Department of Transportation Transportation Systems Center Kendall Squar~ Cambrido-e MA 11 2142 16. Abstract Existing freight car braking systems, components, and sub systems are characterized both physically and functionally, and life-cycle costs are examined. Potential improvements to existing systems previously proposed or available are identified and described in functional and economic terms. Innovative braking systems which offer a potential benefit are identified, described, and assessed for functional and economic characteristics. Potential improvements are divided into two categories: those which could be implemented in the short term (10 years) and those which could be implemented in the long term (20 years). Areas which need additional study are identified. 17. Key Wards 18. Distribution Statement Rail Fteight Braking Systems DOCUMENT IS AVAILABLE TO THE U.S. PUBLIC Rail Freight Equipment Technology THROUGH THE NATIONAL TECHNICAL INFORMATION SERVICE, SPRINGFIELD, VIRGINIA 22161 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price UNCLASSIFIED UNCLASSIFIED 140 Form DOT F 1700.7 <8-72) Reproduction of completed page authorized PREFACE The work described in this report was carried out under the direction of the Transportation Systems Center of the U. s. De partment of Transportation in the context of an overall project of the Federal Railroad Administration (FRA) to provide a techni cal basis for the improvement of rail transportation service, efficiency, productivity and safety. The work was sponsored by the FRA Office of Research and Development, Office of Freight Systems. This final report is organized into two volumes. Volume I describes the work performed and presents the results of the study and is a complete report. Volume II contains supporting materials developed in the course of the study which add substantially to the information base but are not essential to the object of the study. Kearney gratefully acknowledges the cooperation of the many railroads, rapid transit companies, manufacturers, research and development organizations, AAR Brake Equipment Committee members and staff, and other interested parties who provided the informa tion required to conduct a professional, objective study. We would also like to thank DOT personnel in the Transportation Systems Center and the Federal Railroad Administration for their cooperation and assistance throughout the course of the study. iii METRIC CONVERSION FACTORS Approximoll Conversion• to Motric M11sures ::: Appro um•t• ConvlrSIOns from Metric Mcnsur•s --:: N N --:: s,.~.~ wa.u v,. Knew Molti,ly ~Y To Fiw4 s.-., ..et W\eo YM how s, llhhi'ly ~, To F1o4 Sy•hl --:: ;; LENGTH 0 LENGTH " ,.,.,,;:.r-.et('l" 0.04 mche~ --:: ": (.9r'lt>rr'I"IOr!' o.• 1nches mete-~s 31 teet h •nches 2,5 rt>nt•rnet~s --:: iTIIIIters , yards ft teet 30 ceot•meters -: vd 0.9 meters lo.•loneter~ 0.6 mrles "" '""'' 1,6 kol~tets -: m•les !:: ·~ -:: AREA AREA -:: =' squ.¥e Cfllt•mt>~teu 0 16 square roches ,.. ~e •nches 6.5 square C!;'ni•IT'l'IE!i'S crr• -:: -~ ~ '"' m' s.qu.Mf! tn(lll!f, 1.2 square yards tt' sq~re feet 0.09 square IT\Etters -:: .,., 2 m' ~relui(YT'If'll!tfS 0.4 square mrles vd square yards 0.8 square "'W!ters ,.. .: ""' :! twl'ct.VP'5 110.000 'l'l) 1.5 ....... square mtles 2.6 square kiiO"f'et~s m•' •~' "" acres o.• hectarf's n. -: < :: MASS (weight) MASS (weight) -= -:: :::: 00:15 ounces 0) 28 grams --:: 9 9'""'• lo.1IQ91"&ml ;.2 pounds lb lb povods 0.45 k•logtc'ln'IS kq '9 t~st10'JCi.oJ' 1.1 5h01'1 11)1'1$ skort tOf's 0.9 toones -:: !2000 lb) --:: s VOLUME -:: VOLUME ... teaspoons l'l"lll•llters mdl,llt.-t·, 0.01 tlurd <"'(.mrf.l'l i•fl' p111{!!1 ,.,.. tablespoon., ,, fY'•II•I•ter1o ~ 2.1 ""' II oz fluid ounce.s J<) .,,ll•ltters n I 1<11!'<, l 06 QU81U "' r:ups 0.14 11\f>l'< o!.,...., O.:lfl gaiiQfl!' ..."' p•nts O.C7 lt!l>rs ~.· ,ut>'< """lf"IS Jt, 1:lrbn. lf•fll "',..;' •"tot"L'"'">PIPIO, 1 l cubH" ~.]-1"\1· ql'" Cl"':\115 0.9S lqr.-r« -:: ~' Q<'II!Yls H '<tf'•<; <~&' cuh•c ft>et 0.03 {lib" '''f'l.;>f<, -: vd'"' cub•c yards 0.76 cut"-•c 'T'>E'I("f\ 1!!!f.'.~_RE~!.'"~ TEMPERATURE (uoct) 9 S (then f ~twe.nhfl•t ,· '""''I• ~ ltlf'l: -"f<\l••ffl J:'l '"Jl'IP"'f.t\ll"fl ., .0.1 fahntnhetl 5 9 taftet c~ts•ut tempenstu,.. subtrf,ctmg ·~·awrl" ., 321 '.' 9~ 6 ?l1 1 41' 80 2t:' Z()(' /•·-=- t 1~0 I .L t··.l. r.J-T1- >I' 't-...l t-·..1.-r~·-ljL. ,-A- , ... t-·L·,.-'-·-'-r..L-~---1 4•' 0 11' 40 ~lj R(l 't'"fl -----l ~ ·•c 37 - · u EXECUTIVE SUMMARY This report is a survey and assessment of freight train braking technology. The historical events that occurred in the development of freight train air brake systems are dis cussed first, followed by a detailed description of the life cycle cost and functional performance characteristics of air brake systems and components, including estimates of the population of the components presently in service. The report then presents an assessment of the overall brake system per formance characteristics as they affect train handling, stop distance, and grade balancing power. Results of implementing innovative variations of the key train braking performance characteristics were investigated using the computerized Train Operations Simulator (TOS) developed by the Association of American Railroads. Finally, conclusions and recommendations were developed that delineate the steps that should be taken to achieve improved freight train braking safety and per formance over both the short and long terms. Volume I of this report was structured to contain the degree of detail adequate to support the findings and conclu sions, without obscuring the pattern in which each section was developed. Volume II contains substantially more technical detail than Volume I, and as such represents an information and data base that supports Volume I. The present freight train air brake system represents the culmination of years of improvement made to the basic brake system adopted in 1933 when the "AB Valve" was approved for general use by the Master Car Builders. This braking system consists of a single pneumatic train line that is manually con nected between cars, and a pneumatic control valve on each car. The single pneumatic train line performs two basic functions: (l) it provides the brake energizing energy for each car in the form of compressed air which is stored in a reservoir on each car, and (2) it communicates control signals in the form of pressure changes which are interpreted by the control valve on each car, which in turn causes the car brakes to be applied and released. Although the basic system initially provided adequate braking performance and safety margins and exhibited favorable v ., cost characteristics, the demands placed upon it over the years have been severe. Freight train tonnages, lengths, and speeds have increased several fold since the turn of the century. To meet these demands, many improvements have been necessary. These include the development of more sophisticated and faster reacting control valves, the introduction of composition brake shoes, the use of welded brake pipe fittings to reduce leakage, improved freight car wheel metallurgy that can withstand in creased thermal loads, and many others. However, these improvements in technology were not totally adequate in preventing a deterioration in freight train braking performance. To prevent this detoriation the industry also re sorted to two supplementary methods of increasing braking le vels to meet these increasing demands. These methods included a general increase in brake system air pressures and increased use of locomotive dynamic brakes. The increases in brake system demands are still occurring, primarily because of the continuing influx of high gross-to tare ratio freight cars into the North American Fleet.