US 3809188 A
A retarder for installation in a railroad classification yard comprises a pair of retarder levers supporting retarder elements engageable with a car wheel. Noise is suppressed by modifying those elements. The levers are actuated by a cylinder assembly presenting opposed piston rods for applying actuating forces, and in order to eliminate any moment arm tending to bend the cylinder or piston rods, the cylinder is supported by a restrainer suspended from the traffic rail in the yard, provision being made for tangential contact between opposed surfaces of the cylinder assembly and the restrainer so that lines of force are constantly concentrated substantially at the axial center line of the cylinder assembly.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Frank et al.
[111 3,809,188 [451 May 7,1974
[ RAILROAD CAR RETARDERS V  Inventors: Earl E. Frank, Tallman, N.Y.;
Glenn R. Graham, Upper Saddle River, NJ. 1
 Assignee: Abex Corporation, New York, NY.
22 Filed: May 1, 1972  Appl. No.: 248,929
 US. Cl. 188/62, 188/251 A  Int. Cl B6lk 7/08  Field of Search. 188/62, 251 A, 251 M, 251 R  References Cited UNITED STATES PATENTS 2,136,370 11/1938 Bockius et al. 188/251 A X 2,217,001 10/1940 Bockius et a1 188/251 M X 3,321,048 5/1967 -Wigton et al. 3,557,910 1/1971 Wilson 3,716,! 14 Beck 188/62 Primary ExaminerDuane A. Reger Attorney, Agent, or Firm James B. Kinzer; Thomas E. Dorn 5 7] ABSTRACT A retarder for installation in a railroad classification yard comprises a pair of retarder levers supporting retarder elements engageable with a car wheel. Noise is suppressed by modifying those elements. The levers are actuated by a cylinder assembly presenting opposed piston rods for applying actuating forces, and in 17 Claims, 12 Drawing Figures PATENTEU 7 9 4 FIG.|
sum 1 or 4 PATENTEDIAY' 7 m4 sleosllae SHEET 0F 4 wOE RAILROAD CAR RETARDERS This invention relates to railroad car retarders and in particular to a retarder of the tye disclosed in U. S. Pat. No. 3,227,246 where the lever arms of the retarder include portions which, during retardation of the car, cradle and support the traffic rail on which the car wheel moves. The lever arms present retarder elements on opposite sides of the traffic rail adapted to clasp and brake a car wheel on the traffic rail. Thus, the car wheel and the traffic rail in effect float on the lever arms so the retarder operates in response to the weight of the car, which is to say that the braking action on the car wheel by the retarder elements is proportional to the weight of the car. When braking action is desired, the retarder elements are spaced apart a lateral dis tance less than the width of a car wheel, and the retarder is actuated by the lateral thrust of a car wheel entering between the retarder elements. When no brake action is desired, the retarder elements are spaced apart a lateral distance greater than the width of a car wheel.
The retarder elements may be spaced apart selectively for braking or no braking, as desired by a fluid operated cylinder having opposed pistons which pivot the levels as described in US. Pat. No. 3,227,246. Carefulstudy establishes that the cylinder system may be subjected to a bending moment likely to damage the piston rods and the and the seals or glands intended to prevent leakage. This can arise by reason of the fact that one piston, because of differences in internal friction, will always precede the other, a circumstance which cannot be avoided, but can-only be countered. Thus when operating fluid is admitted to the cylinders, one of the pistons is bound to advance first, causing the cylinder to move or react in the opposite direction which is the principle of a thrust motor. Such reaction cannot be avoided, but can only be countered or equaled.
In view of the foregoing, the primary object of the present invention is to devise a cylinder and piston rod actuator for a railroad car retarder which in effect recognizes and counters the mechanical proposition that one of the pistons is bound to move ahead of the other, causing a reaction in the cylinder. More specifically, it is an object of the present invention to cope with the reaction thrust in the cylinder by so supporting the cylinder that the lines of force will always be on the center line of the pistons rather than on a line of force tending to bend the piston.
To be yet more specific an object of the present invention is to cradle the assembly, including the pistons, in a restrainer suspended from the traffic rail, opposed surfaces of the cylinder assembly and restrainer being in tangential relation so that the reaction to cylinder thrust, reacting to one of the pistons advancing ahead of the other, will occur along the axis of the cylinder assembly and not at an angle thereto. Related objects of the invention are to construct the cylinder assembly as one characterized by a medial head to which the two cylinders are connected, the head having opposed arcuate surfaces affording the tangential relation earlier referred to; to provide a port in the head communicating with both cylinders for admitting fluid under pressure concurrently thereto when the piston rods are to be extended; to equip the opposed ends of the cylinder with ported caps so that a manifold may be connected thereto for supplying fluid under pressure concurrently to both cylinders when the piston rods are to be retracted; to construct the cylinder restrainer of two like parts so that it may be easily and readily assembled on the traffic rail; and to so construct the cylinder restrainer as to allow for relative movement between it and the traffic rail.
Retarders of the kind involved are. used in. railroad classification yards. A great deal of noise is sometimes encountered when the retarder forces are applied to thereof and what is now considered to be the best mode.
contemplated for applying that principle. Other embodiments of the invention embodying the same or equivalent principles may be made as desired by those skilled in the art without departing from the present invention.
In the drawings:
FIG. 1 is a sectional view of a railroad car retarder to which the present invention may be applied;
FIGS. 1A and 1B are fragmented views similar to FIG. 1;
FIG. 1C is a sectional view showing how noise suppression may be achieved;
FIG. 2 is a plan view of the actuator of the present invention;
FIG. 3 is an elevation of the cylinder subassembly substantially on the line 33 of FIG. 2;
FIG. 4 is a top plan view of the sub-assembly shown in FIG. 3;
FIG. 5 is an elevation on the line 5-5 of FIG. 4;
FIG. 6 is a perspective, somewhat schematic, of the sub-assembly of FIG. 3;
FIG. 7 is an elevation of the actuator shown in FIG.
castings; and I FIG. 9 is a sectional view on the line,9-9 of FIG. 8.
Before explaining the details of the present invention,
the car wheel as described in US. Pat. No. 3,227,246.
When in a cocked or closed position, FIG. 1, the elements 15 are spaced apart a distance less than the width of the car wheel, so that their wheel-engaging surfaces 22, when engaged with the sides of the wheel, are forced outwardly by the car wheel moving therebetween. Each of the retarder elements is supported by a lever 25 pivotally mounted on an eccentric portion 26 of a rock shaft 28 whichspans a pair of adjacent railway ties T. In this regard, each rock shaft 28, its eccentric 26, and the related supports are similar to the ar- FIG. 8 is an elevation of one of the cylinder restrainer r rangement disclosed in FIGS. 13 to 16 of US. Pat. No. 3,227,246.
The retarding elements are subjected to large laterally directed forces as the railroad car wheel moves therebetween. The lateral forces or thrusts are of course transmitted to the levers 25. The levers 25, however, provide not only monolithic structural members which support the retarder elements 15, but also afford cradle portions 45 for supporting the traffic rail 18. In this sense, the traffic rail floats on the cradle 45, and the weight of a car tends to depress the traffic rail.
Additionally, the levers 25 serve as the means whereby a retarding force may be exerted on the car wheel in proportion to the weight of the car being supported by the car wheels. In this connection, it will be observed that the lower or inner ends of the levers 25 are configured to embrace and support the traffic rail 18. More specifically, the movement of a car wheel through the retarding system 13 establishes lateral thrust, causing each lever arm 25 to pivot about the eccentric portion 26 of the related rock shaft 28 to lift the traffic rail 18 by virtue of the construction at the inner ends of the levers 25. The heavier the weight of the'car, the greater will be the force resisting the lifting of the traffic rail 18 and the car wheel, and hence the greater the force attempting to turn the levers 25 in an opposite direction about the related rock shaft 28 to bring the abrasion rails 15 into tighter and greater frictional engagement with the sides of the car wheel. Thus, for heavy cars, the amount of frictional force retarding the car will be greater than that for a lighter railway car, holding the braking rails 15 in tighter engagement with the sides of the car wheel.
The cradle portion 45 of each lever 25 has a central hump or rounded projection presenting a surface 46 in engagement with the under surface of the flange or base 48 of the rail 18. In addition to the supporting surface 46, the cradle 45 for the rail 18 includes an overhanging lip or flange 49 and the inner end of each lever 25 forming a pocket 50 for a wobble block 50A, bifurcated at the inner side to loosely embrace the base 48 of the traffic rail 18. The wobble block is thus supported by the rail base for universal movement, maintaining solid engagement with the lever arm 25 and the traffic rail 18 during the time a car wheel traverses the retarder. The lever 25 is pocketed to receive loosely the wobble block 50A opposite rail 18.
Since the opposed levers 25 both have overhanging flanges 49 and wobble blocks 50A on opposite sides of the traffic rail 11, the pockets 50B serve in the aggregate to hold the traffic rail 1 1 against both lateral movements and rotational movements on the surface 46 of their respective cradles 45. The flanges 49 are also important from the standpoint that when the retarder system 13 is actuated to an ineffective position, the flanges 49 assure that the levers 25 are supported by the traffic rail 18 which rests on the surfaces of the railway ties T when the car wheels pass thereover.
Thus it will be seen that when a lever 25 is pivoted outwardly by a car wheel entering the retarder, the inner end of each lever 25 tends to be moved upwardly, lifting the traflic rail 11 off railroad tie T. The levers 25 thus act as large bell cranks. The upper arm of this bell crank presents the retarder element 15, the lower arm of this bell crank supports the traffic rail 18, and the pivotal axis of the bell crank is the rock shaft eccentric 26.
For the purposes of receiving a rotational force to rotate each rock shaft 28, the eccentric portion 26 thereof extending beyond the tie T is provided with a downwardly extending crank arm 51, the crank arm 51 being pinned or otherwise fixed thereto. Each crank arm 51 has an aperture 52 formed in the lower end to receive a pin.
Consideration will now be given to operational characteristics of the levers 25, as an introduction to the problem giving rise to the present invention.
It is necessary to open or spread the retarder elements to release the car and thereafter to reset the car retarder to the state shown in FIG. 1 where the retarder elements 15 are spaced apart one from the other less than the width of a car wheel. Thus the retarder elements may be retracted or opened by moving the crank arms 51 inwardly and afterwards the retarder elements may be reset or advanced inward toward one another to the closed position shown in FIG. 1 by forces applied in an opposite sense. The retarder levers 25 only rotate on the wobble blocks 50A during actuation of the crank arms.
As noted the cranks or arms 51 are pinned or otherwise fastened to the eccentric portions 26 of the rock shafts 28. Hence when a rotating force is applied to the cranks 51, rotative forces are applied to the shafts 28.
FIG. 1A corresponds to FIG. 1 in that the left hand crank 51 is in the position it occupies when the retarder is closed. The retarder elements 15 are located in full FIG. 1B shows the position of the left hand crank 51 in the open condition of the retarder, and it can be recognized that crank 51 was rotated in a counterclockwise direction from the position shown in FIG. 1A. Of course the opposite crank arm (not shown in FIG. 1B) moves in a clockwise direction; the levers 25 pivot about the wobble blocks 50A, and in so doing move to the dotted line position shown in FIG. 1A where the inner surfaces of the retarder are spaced apart a greater distance than the width of the car wheel.
Elimination of any appreciable moment arm on the cylinder assembly during actuation is one of the main objects of the present invention, accomplished by the actuator apparatus 60, FIGS. 2 and 7, developed in recognition of the fact that there can be no prediction regarding the comparative rate of travel of two pistons for operating levers 51 with the result that there will always be a reverse or counter thrust on any piston and cylinder assembly used to actuate concurrently the cranks 51.
Basically the present apparatus comprises a pair of cylinders 62 and 63, FIGS. 2 and 7, joined rigidly as a unit to a head or block 64, the latter being cradled within a cage 65 afforded by a cylinder restrainer suspended from the traffic rail 18. The cylinders 62 and 63 are disposed on a common horizontal axis. Each cylinder, by definition, includes a piston therein, and related piston rods 72 and 73 extend outwardly therefrom on the aforesaid horizontal axis. The outer or free end of each piston rod is provided with a clevis, 74 and 75, and each clevis in turn carries a pin, 78 and 79, which will be disposed in the related aperture 52, FIG. 2, of the related crank 51.
The cylinder head or block 64, FIG. 7, is provided with a port 80 and internal passages (not shown) establishing communication with the inner ends of the cylinder chambers so that fluid under pressure admitted to port 80 will extend the piston rods. On the other hand, end caps 82 and 83 are secured to the outer ends of the cylinders and each is provided with a port 85, FIGS. 3
and 7. The opposite ends of a manifold 90, FIG. 2, are
connected respectively to the ports 85 so that fluid under pressure furnished to manifold 90 will be concurrently supplied to. the outer ends of the cylinders to retract the piston rods.
It is known from U.S. Pat. No. 3,227,246 to use a cylinder and apair of piston rods to apply rotative forces to the cranks 51, but as mentioned above, factors such as uneven fluid flow, internal friction, and the like result in the tendency for one piston rod to advance, or
retract as the case may be, ahead of the other so that there is always a counter thrust on the cylinder. In accordance with the present invention the corrective measure is attained by so restraining the cylinder that lines of force will always be substantially on the center line of the cylinder and piston -assembly, thereby eliminating any appreciable moment arm. Additionally provision is made for relative creep or movement between the traffic rail 18 and the cylinder restrainer'70.
Referring to FIGS. 3 and 4, the two cylinders 62 and 63 are integrated to the head 64 at their inner ends. In like fashion, the end caps 82 and 83 are joined to the outer ends of the cylinders. As mentioned above, the head 64 is provided with a port 80 for the admission of fluid under pressure, and such may be supplied through a hose 93 in turn connected to a mainline pipe 94, FIG. 2. The porting of fluid under pressure to the inner ends of the cylinders, to extend the pistons, is a matter of expediency and is no part of the invention; this is equally true of seals and packing. The only requirement is that fluid under pressure for advancing the piston rods be ported concurrently to the inner ends of the cylinders 62 and 63.
The end caps 82 and 83, FIG. 4, are provided with respective ports 85, as noted, which in turn communicate with opposite ends of the manifold 90, as shown in FIG. 2, so that fluid under pressure may be applied concurrently to the outer end of the cylinders to retract the piston rods. Again the precise form of passageways, seals and the like is a matter of expedience and constitutes no part of the present invention, but it may be noted, FIG. 2, that the manifold receives its supply of fluid under pressure from a hose 95 in turn connected to a main line pipe 96.
Preferably the piston rods are protected by dustproof boots 97 of conventional form. The outer or free ends of the piston rods are threaded as shown in FIG. 2 so that clevises 74 and 75 may be accordingly secured thereto. The cylinder unit as a whole is braced by tie rods 98, FIGS. 3 and 4.
0f principal importance under the present invention is the fact that the cylinder assembly 60 and cylinder restrainers 70 are articulated with respect to one an-.
other, and the restrainer is free to rock on the traffic relatively small angle. In achieving'this a tangentialre lation is established between the head 64 and the opposing surfaces of the cylinder restrainer. The entirety of this relationship will be evident as the disclosure progresses, commencing with the observation that the head 64, as best shown in FIGS. 4 and 6, is provided with two outwardly extended bosses 100 having curved outer sides 101.
The cylinder restrainer, featuring as an aspect of the present invention, comprises two castings of identical form, each identified by reference character 105, FIGS. 7, 8 and 9. A description of one suffices as a description of the other. Thus the cylinder restrainer casting includes a horizontal cross web 106, FIG. 8, of bifurcated section, FIG. 9, affording a-pair of jaw ele ments 107 and 108 spaced vertically one from another so as to embrace the related side of the base 110 of the traffic rail 18. The configuration of the jaw is such as to afford clearance between the upper side of the rail base 110 and the opposed surface of the upper jaw element 107, as will be readily apparent from FIG. 7. The lower jaw element is arched, FIG. 9, so as to afford a protuberance 112 engageable with the lower face of the base of the rail as will also be evident in FIG. 7.
Each restrainer casting 105 includes a pair of dependent legs ll5, FIG. 8-. The lower ends of the legs, FIGS.
7 and 9, are provided with inwardly directed lugs 116, the inner ends of which are serrated or toothed at 116T, FIG. 9, so that the two legs, FIG. 7, may be meshed or interfitted at the lower ends beneath the traffic rail. It may be mentioned at this point that the castings 105 are neither left hand nor right hand.
Referring to FIGJS, the lugs 116 are provided with apertures 119 enabling tie bolts 120, FIG. 7, to be entered therein to secure the lower ends of the castings 105 one to another. In like fashion, FIGS. 7, 8 and 9, protuberances 125 immediately adjacent the lower jaw 108 extend outward therefrom and are formed with serrations 125T at their inner ends adapted to mesh with one another, as shown in FIG. 7, in the manner of the serrations 116T. The protuberances 125 are provided with apertures 126, FIG. 8, enabling tie bolts 128 to be entered therein in the fashion of the tie bolts 120.
It will be seen from this that the cylinder restrainer as a whole is assembled from two identical castings 105, and in their assembled form provide a housing or cage 65, FIG. 7, in which the cylinder head 64 may be located. In this connection it is of significance to note that in assembling the actuator as: a whole the clevises 74 and are adjusted so that the pins 78 and 79 thereof may be entered in the apertures 52, FIG. 1, of the cranks 51. In effect the actuator 60 is suspended from and supported by the cranks 51 which is to say that the axis of the cylinder assembly, the axes of the two piston rods and the centers of the apertures 52 are on a common horizontal line. Afterwards, the restrainer castings are assembled relative to the traffic rail and are secured as a unit by the tie bolts 120 and 128. When this is accomplished, the curved surfaces 1010f the cylinder head bosses, FIG. 7, are in engage ment with the inner surfaces of the legs of the restrainer castings.
It will be seen that with the curved surfaces 101, FIG. 7, being opposed to the inside, planar faces of the restrainer castings 105 any longitudinal thrust in the cylinder assembly, in either direction, depending upon which of the pistons is first actuated, will result in the curved surface 101 being thrust against the adjacent restrainer casting 105. It may be mentioned at this point that in FIG. 7 the cylinder assembly is shown in an elevated position within the cage, characteristic of the retarder elements 15, FIG. 1A, in their closed position. If the piston rods 72, FIG. 7, are retracted inward to open the retarder elements, then the cylinder assembly including the head 64 moves downward within the cage 65. Thus, the cylinder assembly rises within the cage opening 65 when the retarder is being closed and falls when the retarder is being opened. This effect can be appreciated by noting, FIGS. 1A and 1B, that the center line of the aperture 52 drops in the course of counter-clockwise movement of crank 51 characterizing opening movement of the retarder elements from their full line position to the dotted line position shown in FIG. 1A.
In any event, and as noted above, there will always be a thrust in one direction or the other when the cylinder is actuated whether actuation be in terms of opening the retarder elements or closingthem. Under the present invention the thrusting of the cylinder head 64 (more specifically one of the rounded bosses 101) against the restrainer assembly 70 will cause the latter to rock on the base of the rail. This accounts for the jaws 107 and 108, FIGS. 7 and 9, being so spread and angled as to allow rocking motion of the cylinder restrainer 70 either clockwise or counter-clockwise on the rail base 110, especially as this is facilitated by the rounded protuberances 112 presented to the rail base by the jaw elements 108.
Therefore cylinder thrust is accompanied by pivotal movement of the restrainer 70 on the base of rail 18, and inasmuch as the outer faces of the bosses 101 are rounded, the point of contact between the cylinder head and the opposed inner surface of the cage structure 65 will always be substantially at point AA or point BB, FIG. 7, on the center line of the cylinder assembly, depending upon the direction of cylinder thrust, and even though the cylinder restrainer casting assembly 70 will rock, nonetheless the tangential contact at point AA or point BB will not vary substantially from the center line of the cylinder and piston axis. In other words, the lines of force resulting from piston rod movement and cylinder reverse thrust will be along the axes of the pistons 72 at the center line of the assembly, whereby any moment arm tending to bend the cylinder is eliminated and the consequence is that the cylinder and piston assembly will be either in compression or tension along the axis and not subjected to any bending moment at an angle to the axis.
It is also significant to note that when a car is retarded there is a tendency for the retarder assembly to shift longitudinally relative to the traffic rail. This tendency is not resisted by the restrainer assembly 70, because the jaws 107 and 108, angled as they are, allow for relative movement, longitudinally, between the traffic rail 18 and the actuator assembly.
Railroad car retarders of the kind involved are installed in railroad classification yards and because of the magnitude of forces, weather conditions and the like, noise of an appreciable order is sometimes generated in the course of applying forces to the wheels of a car. Consequently it is advantageous from the standpoint of environment control to suppress noise, if possible, and in accordance with the present invention this may be accomplished by associating with one or both of the retarder elements 15 an attachment or insert which will afford more quiet action while still affecting the desired application of frictional forces to the car wheel. One mode of achieving this is shown in FIG. 1C where the retarder element in the form of a rail 15A is provided on the wheel side with a bar 135. The rail element 15A is chamfered at 136 to afford a recess, complemental to the adjacent sides of the bar 135, the latter being secured in place as by welds 137. The recess presents a horizontal ledge or shoulder L which re sists the downward force component exerted on bar 135 at the time of wheel engagement.
The bar 135 is a ferrous metal casting incorporating a segment 140, which is to say that the insert 140 of the character hereinafter described, may be produced independently as an integral structure and subsequently located in a mold as a mold insert. Thereafter the molten metal for bar 135 is introduced into and allowed to solidify in the mold where the insert 140 is presented. The outer face of the insert 140 and the adjacent exterior surfaces of the of the casting 135 are engageable with the wheel. As shown in FIG. 1C retention of the insert 140 is further assured by constructing the latter of dove-tail form thereby establishing a mechanical interlock. Advantageously the retainer bar 135 and the insert 140 may be of relatively short length so that a plurality may be arranged in tandem, end-to-end along the length of rail 15A, each separate attachment being welded in place.
The insert 140 is responsible for noise reduction in that it is a body of sintered iron powder incorporating particles of a lubricating material such as graphite or particles of molybdenum sulfide (see Canadian Pat. No. 604,776) or both. To assure the desired friction level the sintered body 140 advantageously contains particles of a friction enhancing agent such as silica, alumina, silicon carbide, sillimanite or the like as disclosed in the Canadian patent. The ratio of lubricating material and the friction enhancing ingredients are adjusted to achieve the desired friction coefficient.
Under present-day circumstances on the railroads, only the retarder element on the gauge side of the retarder need be equipped in accordance with FIG. 1C. The gauge side is the inside of the wheel; the outside of the wheel is the field side. The reason for this is that many cars are equipped with the so-called segment bearing housed in an oil-filled journal box located on the field side of the car truck, and oil is frequenty spilled, leaked and splashed on the outside of the wheel, whilst the inside of the wheel remains dry giving rise to the noise problem. Consequently, and referring to FIG. 1, the retarder element 15 at the gauge side of the wheel (assumed to be the left-hand element 15) need incorporate what is shown and described in connection with FIG. 1C.
1. In a railroad car retarder including a pair of oppositely pivoting levers which support, at their inner ends, retarding elements on opposite sides of a traffic rail for applying retarding forces to opposite sides of a car wheel on the traffic rail: apparatus for applying an actuating force to pivot the levers and comprising a head to whichtwo oppositely extending horizontally disposed cylinders are secured as a unit, a piston rod in each cylinder operable to apply an actuating force respectively for each lever when fluid under pressure is admitted to the related cylinder, a cylinder restrainer adapted to fit the traffic rail in suspended relation thereto, said restrainer presenting a cage for confining the head, and opposed surfaces of the head and cage being in tangential relation.
2. Apparatus according to claim 1 wherein the support includes jaw elements for engaging the base of the traffic rail with clearanceallowing the rail and the restrainer to shift one relative to the other and allowing the restrainer to rock on the base of the rail.
3. Apparatus according to claim 1 wherein at least one of the retarder elements at the surface adjacent the traffic rail carries a bar attached thereto, the bar on its outer surface having an insert of sintered metal containing a particulate lubricant.
4. Apparatus according to claim 1 wherein the tangential relation is presented by curved surfaces on the head engaging opposed surfaces of the cage.
5. Apparatus according to claim 2 wherein the restrainer comprises two separable members.
6. Apparatus according to claim 1 wherein the head has a port to admit fluid under pressure concurrently to both cylinders to extend the piston rods, wherein caps are secured to the ends of the cylinders opposite the head, each of said caps having a port to admit fluid under pressure to the related cylinder, and a manifold communicating with the cap ports to admit fluid under pressure concurrently to both cylinders to retract the piston rods.
7. Apparatus according to claim 5 wherein the tangential relation is presented by curved surfaces on the head engaging opposed surfaces of the cage.
8. Apparatus according to claim 6 wherein the tangential relation is presented by curved surfaces on the head engaging opposed surfaces of the cage.
9. In a railroad car retarder including a pair of levers having ends pivotally supported on opposite sides of the base of a traffic rail and extending outwardly and upwardly therefrom each to present a retarder element at the side of the rail opposite the related pivot, and wherein the levers are supported eccentrically on rock shafts so as to be closed or opened respectively upon rotation of the rock shafts to engage or disengage the retarder elements as to a car wheel on the traffic rail, crank arms fixed to the rock shafts and an actuator assembly to apply actuating forces to the crank arms to rotate the rock shafts, said actuator assembly comprising a head to which two oppositely extending horizontally disposed cylinders are secured as a unit, a piston rod in each cylinder operable to apply an actuating force respectively for each crank arm when fluid under pressure is admitted to the related cylinder, a cylinder restrainersuspended from the traffic rail and adapted to rock relative thereto, said restrainer presenting a cage confining the head, and opposed surfaces of the head and cage being in tangential relation.
10. Retarder apparatus according to claim 9 wherein the support is configured to fit the traffic rail with clearance allowing the rail and the restrainer to shift one relative to the other.
11. Retarder apparatus according to claim 9 wherein at least one of the retarder elements at the surface adjacent the trafi'ic rail carries a bar attached-thereto, the bar on its outer surface having an insert of sintered metal containing a particulate lubricant.
l2. Retarder apparatus according to claim 9 wherein the tangential relation is presented by curved surfaces 7 on the head engaging opposed surfaces of the cage.
13. Retarder apparatus according to claim 10 wherein the restrainer comprises two separable members.
l4. Retarder apparatus according to claim 9 wherein the head has a port to admit fluid under pressure concurrently to both cylinders to extend the piston rods, wherein caps are secured to the ends of the cylinders opposite the head, each of said caps having a port to admit fluid under pressure to the related cylinder, and a manifold communicating with the cap ports to admit fluid under pressure concurrently to both cylinders to retract the piston rods.
15. Retarder apparatus according to claim 13 wherein the tangential relation is presented by curved surfaces on the head engaging opposed surfaces of the cage.
16. Retarder apparatus according to claim 14 wherein the tangential relation is presented by curved surfaces on the head engaging opposed surfaces of the cage.
17. In a railroad car retarder including a pair of elongated retarding elements on opposite sides of a traffic rail for applying retarding forces to opposite sides of a car wheel on the traffic rail, the improvement for suppressing noise characterized by at least one of the retarder elements having a bar attached thereto and secured in a recess therein, said recess affording a hori-' tered metal containing a particulate lubricant.