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Publication numberUS1681131 A
Publication typeGrant
Publication dateAug 14, 1928
Filing dateJan 14, 1926
Priority dateJan 14, 1926
Publication numberUS 1681131 A, US 1681131A, US-A-1681131, US1681131 A, US1681131A
InventorsCharles W Prescott
Original AssigneeGen Railway Signal Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Railway-car-classification system
US 1681131 A
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Description  (OCR text may contain errors)

Aug. 14, 1928.

c. w. pres sco-rr RAILWAY GAR CLASSIFICATION SYSTEM l iled Jan. 14, 192a I arm-(nut Patented Aug. 14, 1928.

UNITED STATES PATENT 0 mm.

CHARLES W. PRESCOTT OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RATB- \VAY SIGLLAL COMPANY, OF ROCHESTER, NEW YORK.

RAILWAY-CAR-CLASSIFICATION SYSTEM.

Application filed January 14, 1926- Serial No. 81,245.

This invention relates to a system for classifying railway cars.

Atthe junctions of various railway systems, and particularly at the larger railway centers, where freight trains are brought in from various directions, it is found that practically all of the cars must be reswitched and reclassified into new trains radiating out in various directions. For this reason it has been found to be expedient to bring these freight trains into a classification yard or system and to re-classify the cars into new trains each of which is made up only of cars having the same destination. This classification or reclassification of cars has generally been accomplished by providing a main track or lead, which is either elevated above the yard or has a hump therein over which the train is pushed, and in allowing one or more cars to be released one at a time, so as to ride off of the hump through a suitable arrangement of switches, which lead to a large number of classification tracks. In order to retard the various cars as they are about to enter their respective classification tracks suitable car retarders or track brakes are employed this in order to reduce the speed to a value at which no harmful impact will occur if they reach cars already standing on such classification tracks. In constructing classification yards of this kind several obstacles are generally encountered; quite often it is necessary to build an artificial hump for accelerating the cars unless the natural layout of the land is such that the desired acceleration maybe obtained from a natural grade; and also, if substantially all of the kinetic energy which is still stored in the cars as they reach the classification track is to be absorbed by retarders or track brakes. it has been found that a large amount of frictional braking of each car is necessary. This latter conclusion, of course, beingbased on the assumption that the cars are accelerated to an appreciable speed in order to increase the classifying capacity of the yard. In other words, since a portion of the yard at least,

namely the main track and certain of the switches, is common to all of the cars to be classified it is readily seen that the cars must move at an appreciable speed in order that the desired number of cars may be classified in a particular period of time, and

in such classification, with the cars accelerated to such a speed a large amount of kinetic energy must be absorbed by the track that there is a certaingrade in the natural contour of the land, and if this is not true such a grade is preferably artificially created, thereby not only forming an accelerating hump but also leaving a decelerating or retarding hump. 'This excavation is preferably such that the momentum a car attains when it enters such excavated or depressed part of the yard, that is when it. goes down the accelerating hump, is sufiicient to carry such car through the necessary switches and again carry it up out of this excavation, conveniently called a retarding hump, and cause it to enter the classification track. In otherwords, it is proposed in accordance with the present invention to employ gravity not only for accelerating the cars but also employ gravity in again retarding the car after it has been diverted into the proper classification track.

Other objects, purposes and characteristic features of the invention will in part appear as the description thereof progresses, and in part be obvious from the drawing.

In describing the invention in detail reference will-be made to the accompanying drawings in which Fig. /1 is a plan layout view illustrating conventionally a railway classification yard laid out and graded in accordance with the present invention; and

Fig. 2 is'a sectional elevation of the yard shown in Fig.1, and more particularly illustrates the general contour of the yard.

Referring to the drawings the main lead or main track 1 has been shown at the extreme left. This main track 1 diverges into two ladder tracks numbered 2 and 3,

respectively. The ladder track 2 has a plurality of classification tracks diverging therefrom of which the tracks l and 5 only have been shown, and from the ladder track 3 diverge a plurality of classification tracks, such as the tracks 6 and 7. The particular track 2 or 3 of these ladder tracks, may be selected by operating the switch S through the medium of a switch machine 3M con trolled by the lever L in the'tower; whereas the classification tracks 1-, and 7 may be selected by the switches S S S and 5 respectively, these switches being operated through the medium of switchinachines $1M controlled by levers L having corresponding exponents. I

In each of the various classification tracks is provided a retarder or track brake, which may be of any suitable type but is preferably a track brake the type and construc tion shown in the application of lVinthrop K. Howe, Ser. No. 70,599 filed November 21, 1925, this retarder being one of the type in which brake shoes on opposite sides of the rails engage and grip the wheel sides of a passing car and in so doing retard the same. by letters R R R R and R and are controlled in a manner as disclosed said Howe application by circuit controllers C having exponents corresponding to those of the retarders which they control. Further, the main lead 1 is also provided with a retarder 'R controlled by the circuit controller 0, whereby the degree of acceleration of a car riding down the accelerating hm 1p All may be selected to a limited extent at least. It is desired to point out at this time that the retarding hump RH represents a vertical incline which is appreciably less than the vertical distance of the accelerating hump. AH, this diiference between the ac-' celerating hump and the retarding or decelerating hump being such that each and every car is assured to roll beyond the retarding hump RH as it moves through the classification yard in the normal direction of trafiic as indicated by the arrow.

During classifying operation a train of cars in preferably pushed from left to right by a locomotive or other suitable means, and as the cars reach the accelerating hump they are released one ata time or in groups having the same destination, and if these cars are extremely heavy, as may be ascertained by, the operator in the tower T by looking at the train sheet he will partially restrict the acceleration of the car as it runs down the acceleratinqhump by applying the track brake R to such a degree as is deemed necessary, so that the cars in each case have the desired speed when passing through the classification portion of the yard, which portion is confined within the space between the accelerating hump All and the retarding These retarders have been designated i,es1,131'

' hump RH. The operator may also asceroperate the retarder of the particular classification track into which the particular car has been switched so that this car may be ultimately retarded to the desired extent.

In certain classification systems where the weather conditions are not very changeable,'

and especially where it is generally Warm and the temperatures do not fluctuate appreciably the retarder R on the-main lead may be omitted, this retarder being particularly used to avoid undue acceleration either because the weight of the car as compared with its rolling friction is high, this ratio varying considerably with the variations of temperature due to gumming up of the lubricant ice and snow on the rails, and the like, or because the particular car in question has very few bends, switches and frogs to take and for this reason should be retarded a littl more by the retarder R on the main track. Also, the retarders in the various classification tracks may not be absolutely necessary depending on local conditions, but are preferably employed in order to restrict the ultimate car speed of the various cars which are classified to substantially the same value, the amount of deceleration or retardation of the various cars naturally being somewhat different by reason of the ratio of the total weight of a particular car to that of its rolling friction. Also, by reason of the'fact that certain cars traverse more curves and switches than do other cars, it is considered expedientif not essential that the track brakes in the various classification tracks be employed.

It is thus seen, that in accordance with the present invention'the cars to be classified are accelerated to a suitable high speed so as to permit a large number of cars to traverse the classification portion of the classification track and be separated and diverted into the proper'classification track within a limited period of time and that the energy necessary to accelerate the cars l higher level) requires less energy to be ab sorbed by frictional braking means, thus resulting in less wear of the track brakes and a a smaller amount of track braking or retarding equipment; that is, less number of rail feet oftrack brakes. Also, the roblem of grading a yard is much simpli ed because the yard as a whole may be substantially level and the classification portion of the yard is a hollowed out or depressed portion of the whole. classification may be obtained solely by excavating. If the natural contour of the land should be substantially level the ground removed from the depressed or excavated portion of the classification yard may be used to raise the level of the main [track or lead 1 toward the'left of the tower ,T. v

i The storage portion of the classification yard, that, is,-the portion to the right of the retarding hump RH is preferably graded so as to have a down grade in the normal direction of traffic ofa value to practically overcome car friction, that is, av downgrade which will under average condition be sufiicient to keep the cars in motion. Although in the particular arrangement shown in the drawings, all of the various remote con trolled devices are controlled from one tower, it is desired to be understood that more than one tower may be used, if desired. For instance, one or more separate retarder towers having levers for controlling retarders may be built at a point where the speed of the cars passing through the retarders beyond the retarding hump RH may be closely observed, or if a single tower is used as shown in the drawings suitable speed indicating means may be employed for indicating to the operator in the tower what the speed of particular car when traversing a particular track portion is. Also 1n the particular arrangement illustrated no 1nclined grading to compensate at curves has been shown, such inclining of the curves in the tracks may be resorted to in accordance with standard track laying practice and if desired the retarding hump of each classification track may be located to suit local conditions in which event the retarding hump will probably be in the form of an arc, also some of the classification tracks may be elevated higher than others so as to compensate for difference in track resistances due to curves and switches of the various classification tracks, if desired.

Having thus shown and described only a single embodiment of the present invention and having shown this embodiment rather conventionally it is desired to be understood that this has been done for the purpose of illustrating the nature of the invention rather than its scope or the exact track layout arrangement or the exact grading preferably employed in practicing the invention; and the various changes and modification may be made to adapt the invention to the particular classification system to which it is: to be applied, without departing from the ,saidinclined track having the desired slope and altitude to bring the cars to a rather high speed; secondly in running the cars up a decelerating incline after they have entered the proper classification track so as to retard themand absord a large percentage only of the kinetic energy stored therein; and thirdly in retarding the cars to the ultimate desired speed on substantially level track by suitable mechanical car retarding means after they have passed beyond the decelerating incline.

2. The method of classifying cars of railway systems which consists in; running the cars one or more at a time down an incline; in switching them into the proper classified track when running at a high speed at the bottom of said incline; and in running them up another but less pronounced incline and then onto a track beyond; whereby the cars are moved for a time at a very high speed and are then again retarded without wasting the kinetic energy stored therein while running at such speed by car braking means.

3. The method of classifying cars of railway systems which consists in; running the cars one or more at a time down an incline; in switching them into the proper classified track when running at a high speed at the bottom of said incline; in running them up another but lower incline; and in retarding the cars to the desired ultimate speed after they have passed beyond said last mentioned incline by suitable mechanical car retarding means.

4-. The method of classifying cars of railway systems which consists in; running the cars down an incline; in operating suitable switches at the foot of such incline to positions so as to divert the car leading to the proper classification tracks to which such switches lead; and in running them up another but less pronounced inclined and onto track beyond for the purpose of retarding the cars and prevent them from colliding with cars standing on such classification tracks, without wasting the kinetic energy stored in these cars; 'whereby the kinetic energy of the moving cars is used in moving such cars to a higher level.

V 5. In a system for classifying railway cars,- the combination with a railway yard having a main track leading into a large number of classification tracks through suitable trac-k switches; power operated means for operating said switches from a distant point the contour of said yard being such that a car moving towards said classified tracks from said main track is run down an accelerating incline so as to reach a rather high speed in passingthrough said switches, and the contour is further such that'the ears in entering their respective classification tracks are required to run up a retarding or decelerating incline insufficient to bring the car to a full stop; and suitable mechanical car retarding means for further retarding the cars after they have passed beyond said retarding incline.

6. In a railway car classifying system, a

railway yard having a main track leading to a number of classification tracks through switches, an accelerating hump and a substantially level portion of track preceding the hump, in the main track, a retarding hump and a substantially level portion of track following the hump, in each of the classification tracks, with the last said level portion of track situated at a lower level than the corresponding part of the main track.

7. In a railwayvcar classifying system, a railway yard having a main track leading to a number of classification tracks through switches, an accelerating hump and a sub-- stantially level portion of track preceding the hump, in the main track, a retarding hump and a substantially level portion of track following the hump. in each of the classification tracks, with the last said level portion of track sitnated at a lower level than the corresponding part of the main track, distance operated power track brakes on the level portion of track of the classification tracks.

In testimony whereof I affix my signature.

CHARLES WV. PRESCOTT.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3093200 *Oct 22, 1957Jun 11, 1963Railroad Machinery Dev CorpSystem and method of weighing coupled railroad cars in motion
US3154023 *Dec 12, 1957Oct 27, 1964Westinghouse Air Brake CoFreight car classification yards
US3169736 *May 6, 1954Feb 16, 1965Gen Signal CorpRailway car retarders and control thereof
US3172490 *Jun 10, 1963Mar 9, 1965Railroad Machinery Dev CorpSystem and method of weighing coupled railroad cars in motion
US3234378 *Feb 13, 1961Feb 8, 1966Gallacher Barnard GRailroad car retarder system
US7742848 *Mar 23, 2006Jun 22, 2010Canadian National Railway CompanySystem and method for computing rail car switching solutions in a switchyard including logic to re-switch cars for block pull time
US7742849Mar 23, 2006Jun 22, 2010Canadian National Railway CompanySystem and method for computing car switching solutions in a switchyard using car ETA as a factor
US7747362Mar 23, 2006Jun 29, 2010Canadian National Railway CompanySystem and method for computing rail car switching solutions by assessing space availability in a classification track on the basis of block pull time
US7751952Mar 23, 2006Jul 6, 2010Canadian National Railway CompanySystem and method for computing rail car switching solutions in a switchyard including logic to re-switch cars for arrival rate
US7792616Mar 23, 2006Sep 7, 2010Canadian National Railway CompanySystem and method for computing rail car switching solutions in a switchyard including logic to re-switch cars for block size
US7818101Mar 23, 2006Oct 19, 2010Canadian National Railway CompanySystem and method for computing rail car switching solutions in a switchyard using an iterative method
US7831342May 6, 2009Nov 9, 2010Canadian National Railway CompanySystem and method for computing railcar switching solutions in a switchyard using empty car substitution logic
US7885736 *May 12, 2010Feb 8, 2011Canadian National Railway CompanySystem and method for computing rail car switching solutions in a switchyard including logic to re-switch cars for block pull time
US7983806May 11, 2010Jul 19, 2011Canadian National Railway CompanySystem and method for computing car switching solutions in a switchyard using car ETA as a factor
US8019497Dec 15, 2009Sep 13, 2011Canadian National Railway CompanySystem and method for computing rail car switching solutions using dynamic classification track allocation
US8055397Nov 17, 2006Nov 8, 2011Canadian National Railway CompanySystem and method for computing rail car switching sequence in a switchyard
US8060263Feb 6, 2007Nov 15, 2011Canadian National Railway CompanySystem and method for forecasting the composition of an outbound train in a switchyard
US8239079Oct 14, 2011Aug 7, 2012Canadian National Railway CompanySystem and method for computing rail car switching sequence in a switchyard
US8332086Sep 30, 2011Dec 11, 2012Canadian National Railway CompanySystem and method for forecasting the composition of an outbound train in a switchyard
Classifications
U.S. Classification104/26.2, 246/182.00A, 177/DIG.800
International ClassificationB61L17/02, B61L17/00
Cooperative ClassificationY10S177/08, B61L17/023, B61L17/00
European ClassificationB61L17/02A, B61L17/00