CA1309700C - Embedded track assembly - Google Patents

Abstract

EMBEDDED TRACK ASSEMBLY
Abstract of the Disclosure An embedded track construction for a transit railway including first and second parallel, spaced rails extending an indefinite length in a first longitudinal direction. A composite insert assembly extends along the indefinite length of the rails to electrically insulate the track rails from the surrounding ground surface. The composite insert also provides a positive water seal and allows lateral movement of the rail. The inserts include a first generally rigid channel and an elastomeric member received thereon. The rigid channel preferably defines an inverted, generally U-shaped configuration in which one leg is interposed between the top and bottom flanges of the rails. A second leg abuttingly engages conventional support ties that are perpendicularly disposed to the transit rails. Gauge side inserts include a cut-out formed in the elastomeric member to receive an associated wheel flange. The inserts facilitate crossing of the railway in a transverse direction, as well as travel in the longitudinal direction by emergency vehicles or the like.

Description

13~7~0 1,~11~1,1)1)1,1) I RACK ASSI,M131,Y

round of the Invelltion _ 111is inve11tio11 pertains to the art Or railway track assemblies an~ 1nore particularly, to embedded railway track co11structions.
Ihe invention is particu1clrly applicable to a mass transit railway construction in wl1ich it is necessary to elnbecl tlle track so tllat it does not extend substantially above tlle finish grade of the surrounding ground surface or pavement. Althoug1~ t1~e inve1ltio11 will be describec1 Witl1 particular reference to an embedded ~, railway construction, it will be appreciate(1 tllat the inventio11 has broader applications anc1 may be advantageously employed in still ot1~er rail enviro11ments and applications.
Mass transit railway constroctions typically 2~ employ a pair of steel rails supported on plural, perpenc1icularly disl)osed concrete ties. A resilient anc1 insulating rubber pad is interposed between the bottom flange portio11 of the generally I-shapec1 rails and the concrete ties. I`hese rubber pads not only electrically insulate the rail from tlle concrete ties but provicle vertical resilience Eor the rail. I`he rubber pads acllieve a predetermined degree of noise and vibration attenuat iOIl .
D~e to the crowdecl conditions and limited area available for mass transit tracks, it l1as become increasi11gly desirable to locate the track in tlle met1ian strip of a right of way for road traffic. Ideally, this track must also be adapted to permit emerge11cy vehicles to not only cross the track Erom one side to the otller, ,. ~
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i. e., in a trallsverse path along the general direction of tlle cross ties, but must also be able to adequately support the emergency vellicles fo~ travel in the longitudillal ~irection, i. e., p~rallel to the rail direction. Since the rail must accommodate emergency vehicles along its longitudillal path, the track rails must be buriecl or embedded to prevent substantial interference with driving thereon.
Another important consideration is tllat the 'O embedded rail constructions be electrically insulated ~rom the surrounding ground. lhis particularly limits tlle types of materials that may be used. l`he embedded track assembly must also be able to withstand predetermillecl bearing load tests. Additionally, inserts or filler suppoIt structures contenlplated for insulating along opposite sides of the rails must be able to comply with minimum deflection requirements. Once again, this particularly limits the type of materials that may be used. Also, the rail must have a positive water seal so that moisture will not collect and cause environmental failures.
In ad~ition to being cost effective and easy to install, the proposecl inserts must also be able to receive conventiollal rail clips tl~at are spaced at predetermilled areas along the lengtll of the rails.
Thus, some type of cavity must be provicled in the inserts at these predetermined areas. Simultaneously, the inserts must be able to sul)port the required bearing loads and still meet the minimum deflection requirements at these rail clip areas.
Convelltional constructions do not contemplate embedding the rail construction along its entire longitudillal length. Instead, the rails and a portion of the support ties are exposed above tlle ground surface. Only preselected road crossings need be incorporated into these systems.

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Altllough many railroad crossing structures are knowll in tlle art, for example, U. S. Patent Nos.
~,36~,845 issued to ~erry, et al. on January 18, 198~;

4,421,272 issued to WJIitlock on ~ecember 20, lg83; and, c 4,445,64~ issue~ to Caillet on May 1, 1984, tllese types of structures are limited in their use because of the higll expense illvolved in tlle structures. Further, none of these patents are directed to embedding the entire track construction along its longituclillal lengtll in lG order to permit not only a transverse crossing of the railways but longitudinal travel by emergency vehicles or other autolllotive vehicles. Tlle present inventioll contemplates a new an(l improved embedded track assembly tllat overcomes all of tlle above referred to problems and otllers and provides a lightweigllt, dural)le, alld economical strs~cture tailored for use in mass transit railway constructions.

Summary of the Invention According to the present inventioll, there is provide(l an insert extencling along the longitudinal length of the parallel rails for electrically insulating the rails from the surroslnding groun(l surface and provides support with limited deflection to accommodate vehicles in either a transverse or longitudinal directioll .
According to a more limited aspect of the invelltion, the inserts include a generally rigid channel defining an open cavity. An elastomeric member is supported along an upper face of the rigid chanllel to provide a resilient nature to the insert.

l .,, ~3~7~0 According to a first embodiment of the invention, the rigid member is of metallic construction that is entirely insulated along any area adjacent tlle associatecl rail.
~ ccording to an alternate embodiment of the invention, tlle rigi~ member is o~ polymeric construction wl~ich is itself an electrical insulator.
According to a still further aspect of tlle invention, a bonding component is used for sealingly interconnecting the rigid member with the elastomeric member.
A principal advantage of the inventioll resides in tl)e dural)le structure adapted for transverse and longitudillal vellicle travel.
1~ ~nother advalltage is found in the lightweight constructioll that facilitates installation.
Yet anotller advantage is realized by the electrical ins-llating properties of the assembly.
Still other advantages and benefits will become apparellt to those skilled in the art upon a reading and understanding of the following detailed description.

~rief DescriPtioll of the Dra~ings 2~
I`he inventioll may take physical form in certain parts and arrangemellts of parts, preferred and alternate embodiments of wllicll will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein:
~ l~UI~B 1 is a perspective view of an embedded track assembly at a grade crossing according to the subject invention;

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FIGUI~E 2 is a vertical cross-sectional view Of the railway track construction ~enerally along the lines 2-2 of ~ JI~
~ IGUR~ 3 is an enlarge(l, perspective view ~ a ~referre~ insert assembly partially broken away to facilitate illustration of tlle various components;
IlGUI~ 4 is an enlarged, cross-sectional view of a first preferred enlbodiment of the subject invelltion; and, llGUR~i 5 is an enlarged, cross-sectional view of a second preferred embodiment.

~etailed Description of the Preferred ~mbodiment 1~
Rererrillg now to tlle drawillgs wl~erein the sllowings are for purl-oses of illustrating tlle preferred and a1ternate embodilllellts of tlle inventioll on1y and not for purposes of limiting same, tlle ~IGUR~S show an 2~ embed(led railwcly track construction A that electrically insulates tlle rails from tlle surroull(litlg groulld surEace.
More particularly, the embedded track constructioll A includes first and second rails 10, 12 eacll havillg a generally I-sllaped cross-section for 2~ supporting an associated wheel l3 of a rail car (not shown). ~ach rail includes an enlarged support flange 14, top flange 16, and a web 18 interconnecting the top and bottom flanges.
I`ypically, the bottom flange 14 is operatively 3~ supported along spaced support ties 24. Modern day constructions utilize concrete support ties and employ a rubber insulating pad 26 between the concrete ties and thc rails, altllougll other supl-ort arrangemcnts can be used without departing from the scope and intent of the ``-6-subject inventioll. Io firmly retain the rails on the concrete ties, conventional rail clips 28 are secure~ to the ties and extend up and over the bottom support flange 14 to clamp the rails. An insulator 30, sucll as a glass-filled nyloll melllber is disposed betwen the rail clip and the bottom support flange to electrically insulate the rail from the rail clip and support tie.
As dcscribecl above, most railway constructions have an open track assembly in whicll the ties are only partially embed~ed in the ground surface. In this manner, the rails are fully exposed above the finish grade. ~s described above and detailed in the noted patents, it is well known to provide a railroad crossing structure that permits traversal of the rails along a 1~ path generally l~erpen(licular to the longitudinal directioll of tlle rails. lllat is, tllese structures are designed to accommodate automotive traffic in a direction generally parallel to tllat of tl~e support ties. Ihese structures, though in widespread use, are extremely expensive and not adapted for emergency vehicle travel in a direction generally parallel with the rails. Still further, these structures are only designed for use at selected regions where a roa~way crosses or intersects with that oE a railroad.
According to tlle subject illvcntioll, alld as illustrated in lIGUI~S 1-3? the embedded track assembly includes inserts C extendillg in operative engagemellt witll opposite sides of each rail along its longitudinal lengtll to entirely insulate tlle rails from tlle 33 surrounclillg groun(l surface D. As will become more apparent below, tlle inserts also provide bearing support for emergellcy vehicles and the like that can travel in tlle direction of the rails. Alternatively, tlle inserts permit transverse crossing of the railway, for example, 3~ at an intersection witll roadway ~.

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7 1 3~7~0 As illustrated in llGUR~S 1 and 2, two sets of parallel rails 10, 12 are disposed for railway traffic in two directiolls. Since tlle right-llallcl and left-halld tracks are o~ identical constructions, like numerals will be used to identiry like elements. A crushed rock subgrade 36 receives a drainage pipe 38, sucl- as a perforated polyvinylchloride pipe, in a centralized drainage recess region 40. A reinforced concrete slab 42 is supported on the crushed stone subgrade and, in turn, supports conventional concrete ties 24. ~nother layer Or cruslled rock 44 is disposed on top of the support ties and an asphalt pavement 46 defines the finish gr~de.
I`he asphalt pavement is disposed on tl-e outer or field side ~ of the rails, as well as tlle gauge side G defined between the irst and second rails 10, 12.
I`l-e devil strip region 48 disposed between adjacent rail pairs also incorporates the asphalt pavement.
Nevertheless, the compacted stone 44 and asphalt is not brought into engagemellt with the rails themselves, which are disposed approximately one illCh l~igller thall the finisll grade of the asphnlt pavemcnt. ln order to accommodate this difference in heigllt, an insulator not only must electrically insulate the rails from the surroulldillg ground surface ~ but must be able to provide limited deflection, e.g., one-~uarter inch maximum deflection, so that an automotive vehicle can travel in the same longitudinal direction as thAt of the rails without adverse effect.
The subject new inserts G are designed for light weight, inexpensive, yet rigid support to provide limited deflection and electrically insulate the rails from the ground surface. ~ first preferred embodiment shown in FIGURB 4 includes a generally rigid member such ~ /, t,~

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as an extruded alumillum channel 54. The challnel is of llollow configuration and has an inverted, generally U-shaped configoration with a dowllwardly extendillg first leg 56 that terminates in an enlarged flange 58. Tlle flange 58 abuttillgly engages the top surface of tllc support tie an(l is secured tllcreto witll a ram set bolt 60 or other conventional astening means. A second leg 62 is disposed adjacent the rail and operatively engages the bottom support flange 14 of the rail. Tlle closed end of the rigid challllel is defined by a transverse connecting web 64 to substantially close cavity 66 definecl by the rigid channel.
The field side and gauge side challnels have a slightly different cross-sectional configuration w11icl is most apparellt in the conllectillg web 64. Ihus, the differing portions of the connecting web of the field side F and gauge side G channels are referenced by separate nulllerals for the sake of clarity. The field side channel includes a first inclined portion 72 that 23 extends between the vertical sccond leg 62 and a generally horizolltal planar region 74. Ihe challnel is oriented so that the second leg is substantially positioned between the top and bottom flanges 14, 16 of tlle rail and generally parallel to the interconnecting web 18 of the rail. Fronl the other end of the planar region 74 extends a vertical portion 76 that merges into a second horizontal portion 78. In this n~anner, the first leg 56 is connected to the second leg to define a generally inverted U-shaped chanllel.
lhe gauge side channel includes first and second horizolltal planar regions 84, 86 interconnected by generally vertically extending portion 88. The first planar region 84 defines a recessed area to facilitate receipt of a rail wheel B as will be described further below.

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An outw~rdly extér,ding leg extension 94 of tlle s~concl l~g 62 is receivecl in an el~stomeric insulator 96. Ille illsulator 96 llas a generally curvi~ ar interior face tllat conforms to the arcu.~te merging a~ea of tlle intercollllectillg web 18 an~ bottom flange 14 of the rail. Ad~litionallyr clistal end 98 of the insulator abuttingly engages tlle nylon insula~or 30 associated with tlle rail clips. I`his abutting engagement between tlle insulators 30, 96 limits horizontal displacement of the secon(l leg 62. Of course, one skilled in the art will realize that tlle conformation of the second leg might be suitably alterecl to accommodate other rail fastenillg arrangemellts without departing rom the scope and intel-t of the invention. In conjunction with the ram set bolt 6() securing the first leg 56, the entire rigid challllel is thereby fixedly securecl relative to the rail and support tie.
rllc second major compollellt of the insert C is an elastomeric slab or yad member lU4. ~n the field side 1, tlle elastomeric member has a generally ~lanar top surface lU6 and a downturllecl regioll 108 that generally conforllls to the vertical portion 7c'~ of the rigicl chanllel An interior face 110 of the elastomeric member closely conforms ancl abuttingly engages the generally l-sllapecl rail as it necks down from the top flange 16 to the web 18. rhe interior face, thought terminates approximately one-third of the way down the interconnecting web of the rail so that a hollow region 112 is defined between the lower portion of the second leg 62 and the interconnecting web 18.
Likewise, the gauge side elastomeric member also includes a generally planar surface region 106 that exten~s inwar~ly from the downturned portion 108 that extends along tlle first leg 56. The gauge side 3 ~3 ~ 7 ~ 0 elastomeric member, thougli, inclucles a recess or cut-out 118 tllat closely follows the vertical portion 88 and the first planar region 84 of the gauge side rigid challnel.
Ihe cut-out 118 freely receives the flange 120 of associatc~ rail wlleel ~. Similarly, interior face 110 of tlle gauge side elastomeric member also generally conforms to tlle I-shaped rail but terminates approximately one-tllir~ of tl~e way down tl~e interconnecting web 18 to define a cavity 112.
A sealing compound 122 is preferably used betweell the elastomeric member 104 and tl~e rail. The compound is designed to eliminate water penetration througll tlle abutting contact surfaces Or the rail and elastomeric member. Likewise, a bonding compouncl 124 is disposecl between the elastomeric member and the generally rigid cl-anllel at selected regions to attain a positive bonding relatiotlsllip tllerebetween.
Witll reference now to FIGUI~ 5, an alternate embodilllellt will be described in detail. Since a 2n substantial portion of the assembly is similar in construction, like elemellts are idelltified by like numerals with a primed (') suffix and new elements are identifiecl by new nulllerals. I`he rigicl chanllcl is preEerably formed of a clurable insulating higll strength plastic. It is molded to include generally vertically extendillg first and second legs 56'ancl G2' intercollnected by a planar region 84'. The first leg 56' extends upwardly from abutting engagemellt with the support tie, while the second leg extends upwardly from abutting engagement with the bottom support flange 14' of an associated rail. ~n angularly extending leg 126 is inclined inwardly toward the rail from the intersection of the first leg portion and the planar region. Ille angular leg deEines an acute angle with planar region 84' and forms a locking arrangement witl tlle elastomeric member 104'.

~ '`~'`l 3 3~7~1 'I`lle elastomeric member includes a generally planar surface 106'. Likewise, the ~auge side has a recess or cut-out 118'. Once again, tlle cut-out is designed to receive the ~lange 120' oE an associated rai~ wl~eel 13'. Since the rigid challnel 54' is of plastic constructioll the insulator, disposed at the lower end Or the second leg in the FlGlJII~ 4 embodiment, is no~ require~. Instead, the secon~ leg direc~ly abuts the bottom support flange 14' of the rail.
1~ A finger portion 128 is formed in tile elastomeric mem~er 104' for cooperation with the angular leg 12~ of tlle rigid plastic channel. The finger extends dowllwardly and outwardly away from tlle rail and is lockingly engaged by tlle angular leg of the rigid 13 challllel. More particularly, the asphalt 46' imposes a vertical downwar(l bearing force componellt on the angular leg to lock tlle finger in place alld prevent upward removal oE the elastomeric mellll)er. Additionally, tlle lateral pressure imposeù by the compacted stone and 23 asphalt retains the entire insert firmly presse(l against tlle associated rail. Furtller, tlle terminatillg support flange 58' of the first leg anchors tlle rigid channel against displacemellt.
A ~air of upwar(lly exten(ling recesses 130, 132 2~ are forme(l in the lower face 134 of the elastomeric slab. 'I'he first recess 13() facilitates removal of the entire elastomeric slab in case of repair. l'hat is, if a lifting force is applied to the elastomeric slab, the groove 130 will permit the finger 128 to extend inwardly 3~ toward tlle rail an(l be relieved o its locking engagement witll the angular leg. 'I'he second recess 132 permits adequate deflection when the rail is loaded under vertical bearing forces and vibratory movements.
In all other aspects, the second embodiment is 3~ substantially similar to that of the first embodiment.

/~ '' 130~7~)0 -lZ-~ ccorcling to tlle above detailed embodiments, the following particulars more specifically describe the typc of materials used:

F I GUR~ 4 ~mbodiment:

~igid channel - Aluminum alloy, metal alloy ~lastomeric menlber - Thermal setting or thermal plastic Sealing compoulld - Cohesive elastomeric material Bonding compound - Cohesive elastomeric material ElGUI~E 5 Embodiment:

5 l~igid cl-anllel - I`hermal setting or thermal polymeric material ~lastomeric member - Thermal setting or thermal plastic Sealing compoun~ - Cohesive elastomeric material ~ ~onding compound - Cohesive elastomeric material The invention l~as been describe~ with reference to the preferred and alternate embodilllents. Obviously, modificatiolls and alterations will occur to others upon a rcading ancl understalldillg of this specification. For example, other light weight rigid materials than aluminulll or plastic can be used with equal success.
Similarly, other compositions can be substituted for the described elastomer without departing from the scope and intent of the subject invention. This specification is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

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Claims (21)

1. An insulated embedded track construction for a transit railway comprising:
first and second spaced, generally parallel rails extending for an indefinite length in a first longitudinal direction;
plural, spaced ties disposed generally perpendicular to the rails in supporting relation thereof;
plural rail clips secured to said ties and engaging said rails at spaced positions along said first direction for fastening said rails to said ties; and, a first composite insert disposed in abutting engagement with said first rail, said first insert extending continuously along said indefinite length in said first longitudinal direction, said composite insert including a first, generally rigid channel having first and second legs extending outwardly from a connecting portion and defining a cavity for receiving said rail clips, and an elastomeric member cooperating therewith.

2. The track construction as defined in claim further comprising second, third, and fourth composite inserts extending said indefinite length in said first longitudinal direction, each of said second, third, and fourth inserts including a first generally rigid channel and an elastomeric member cooperating therewith.

3. The track construction as defined in claim 2 wherein said first and second inserts are disposed in abutting engagement with said first and second rails, respectively, along inner faces of said rails, said first and second inserts each including an arcuate cut-out for receiving an associated wheel flange of the transit railway.

4. The track construction as defined in claim 1 wherein said second leg operatively engages a bottom flange of the first rail.

5. The track construction as defined in claim 4 further comprising an insulator interposed between said second leg and said bottom flange of the first rail.

6. The track construction as defined in claim 1 wherein said first leg operatively engages said ties.

7. The track construction as defined in claim 6 further comprising a leg extension extending outwardly from said connecting portion oppositely from said first leg.

8. The track construction as defined in claim 7 wherein said leg extension defines an acute angle with said connecting portion.

9. The track construction as defined in claim 1 wherein said elastomeric member abuttingly engages said rigid channel along said connecting portion.

10. The track construction as defined in claim 1 wherein said rigid channel is an aluminum composition.

11. The track construction as defined in claim 1 wherein said rigid channel is of plastic composition.

12. The track construction as defined in claim 1 further comprising a bonding component for sealingly interconnecting said rigid channel and elastomeric member.

13. The track construction as defined in claim 1 further comprising an insulator operatively disposed at an outer terminal end of said rigid channel for electrically insulating said channel from said first rail.

14. The track construction as defined in claim 1 further comprising a sealing compound for sealingly interconnecting said elastomeric member and said first rail.

15. The track construction as defined in claim 14 wherein said elastomeric member closely conforms and abuttingly engages said first rail from a rail top flange to a rail web.

16. The track construction as defined in claim 15 wherein said elastomeric member terminates approximately one-third of the way down said rail web to define a hollow region between said second leg and said rail web.

17. The track construction as defined in claim 1 wherein said second leg of said channel is substantially disposed between a top flange and a bottom flange of said first rail.

18. An embedded railway track construction comprising:
first and second substantially parallel rails defining a longitudinal path of indefinite length;
ties supportingly engaging said first and second rails;
means for fastening said rails to said ties; and, an insert having a continuous longitudinal dimension substantially co-terminuous with said first and second rails, said insert including a first generally rigid portion having first and second legs extending outwardly from a connecting portion and defining a cavity for receiving said fastening means, said insert further including an elastomeric member operatively engaging said rigid channel along a first face that is oppositely disposed from said cavity.

19. The embedded track construction as defined in claim 18 wherein said first leg operatively engages said ties and said second leg operatively engages a bottom flange of said first rail.

20. The embedded track construction as defined in claim 19 further comprising an insulator interposed between a terminal end of said second leg and said bottom flange of said first rail.

21. The embedded track construction as defined in claim 18 wherein said elastomeric member includes an arcuate cut-out for receiving an associated railway wheel flange.