DESC: DESCRIPTION

SWITCH EXPANSION JOINTS WITHOUT ANY CUT/GROOVE ON GAUGE FACE OR NON GAUGE FACE

FIELD OF INVENTION:

The present invention relates to an improved Switch Expansion Joints (SEJs) for use in railway tracks particularly to rail expansion joint also known as switch expansion joint (SEJ) for use in railway tracks at the end of long welded rails fitted to the sleepers. The ISEJ installed at either ends of LWR to allow longitudinal movements owning to its special designs, consisting of a pair of fabricated stock rails and a pair of tongue rails at either ends. The arrangement of Cut and machined portion for expansion and hugging respectively falls at gauge face side (1). The machined portion of tongue rail and inner stock rail hugging each other starts and terminates within the only sleepers (3) at either ends of fabricated stock rail.

SEJ is used to take care of the expansion in a long welded rail and is placed at two ends thereof. SEJ may be connected to a long welded rails only on one side or on both sides.

BACKGROUND OF THE INVENTION

A switch is a device that enables the train to change its track enabling it to proceed in the correct direction. This SEJ is a device, installed at the end of LWR/CWR, to allow the longitudinal movements in the breathing length due to temperature variations or we can say it is a device that compensates the natural changes in the track due to temperature variations and protects the technical standard dimension of the same.
In the prior art, earlier switch expansion joint comprised of one accomplice rail (herein known as tongue rail) along with the incoming main running rail (herein known as stock rail). For brevity, the side of the rail head which guides the wheel flange is called Gauge face. In this said assembly, the incoming main rail (stock rail) involves cut followed by machined/bent portion of stock rail to accommodate the accomplice rail (tongue rail), after its cut & hugging with stock rail in its machined/bent portion. The tongue rail after the cut in stock rail forms the gauge face. On either side of the assembly of SEJ, the main running rail forms the gauge face to guide the wheel. The assembly at either end thus consist of pair of one Tongue Rail & one Stock rail on left hand side as well as on right hand side. These tongue rail & stock rail, bent & machined cater for expansion of long rail.

Improved switch expansion joints (ISEJ)

Later, a need of change /advancement was felt on to improve the service life of SEJ by introducing ‘Improved Switch Expansion Joint’ of which either of the tongue rails & stock rails were bend free.
Improved SEJ of two designs, one with single gap of maximum 80 mm and another with double gaps of maximum 65 mm were adopted for regular use on Indian Railways in May 2008. Intellectual Property Right (IPR) of Improved SEJ were transferred to Indian Railways by the respective firms holding the patent through a Patent License Agreement. Accordingly, Improved SEJs of with these designs i.e.single gap and double gap are being manufactured and laid on Indian Railways.

a) Single gap ISEJ

The design consists of three sections of rails, the tongue rail, Stock rail and gap avoid rail. Both tongue rail as well as stock rails of 1200 mm and 1180 mm respectively are incoming running rails on either side of the assembly and are laid both for left hand and right hand. Gauge face of tongue rail and gauge face of stock rail are available, one by one, for the flange of wheel to negotiate these rails, for their respective lengths. Cut are provided on one extreme end of the assembly in the tongue rail and on other extreme end of the assembly in the stock rail on non-gauge face side followed by machined portion of 1200mm & 1180mm respectively. After the cuts, almost the entire length of the tongue rail and stock rail are machined on non-gauge face side. In between two cuts at the either ends of the assembly, the gap avoiding rail is placed against the stock rail and tongue rail on their non-gauge face side. Gauge face of tongue rails and stock rails is thus encountered by the flange of wheel to negotiate, opposite to the cut and machined portion provided in these two rails.

b) Double Gap ISEJ

The design consists of three sections of rails, two incoming tongue rails at either ends of long rail of around 610 mm each and in between these two tongue rails is placed a fabricated stock rail. Both tongue rail are incoming running rails on either side of the assembly and are laid both for left hand and right hand. Gauge face of both the incoming tongue rails and the gauge face of the fabricated stock rail provide, gauge face for the flange of wheel to negotiate in their respective lengths. Cuts are provided in the incoming tongue rails i.e. on the extreme end of the assembly in the tongue rails on non-gauge face side followed by machined portion of tongue rail on either ends for a length of 610mm. Gauge face of both the tongue rails is thus encountered by the flange of wheel to negotiate, opposite to the cut and machined portion provided in these two rails.

In the prior art, an assembly of two pairs was provided at either end to cater for longitudinal movement of rails due to temperature variation.

Each pair consisted of one tongue rail & one stock rail. Tongue Rail & Stock rail were bent and machined to cater for expansion of long rail. Tongue rail forms the gauge face, from the point of the cut and machined portion in stock rail.

In the SEJ, no fracture complained in Tongue Rail because no groove in Tongue Rail head at non-gauge face side while stock rail was having groove at gauge face. Stock Rail got fractured at toe side, which was strengthened with RF Strap on web of stock Rail later.

Railway Board ordered to stop the use of both these SEJs because of lot of fractures took place.

Though these “Improved SEJs” were considered to have definite advantages over the conventional SEJs due to no bends in stock and tongue, RDSO has taken note of many instances of crack/fracture of tongue and stock rails of Improved SEJs in field in service. The cases of loosening and breakage of HTS bolts used in fabrication of stock rail have also been reported since last many years.
Both these designs are sensitive to any situation which creates unwanted additional stress in cut and machined portion of tongue rail area on non-gauge face side. This is likely to be more in case of single gap ISEJ because of gap avoiding rail may not give that sound effect as fabricated rail and further area of improper attention will be more.

DESCRIPTION OF THE INVENTION:

Rail movement joints are required when tracks are laid across engineering structures such as bridges and via ducts. These structures are exposed to changes in lengths due to ambient influences like traffic load, temperature and wind. These influences sometimes lead to angular rotations of the end spans in the abutment. Rail movement joints are installed to bridge such length variations and, if required to accommodate angular rotations of the end spans.

According to this invention, switch expansion Joint is a device installed at the end of LWR to allow for longitudinal movements in the breathing length due to temperature variations.

The object of the invention is to develop a device ensuring, there is limited variance in the parameters of the track so that there is no hindrance created in the passage of the wheel over it. Both expansion and contraction are dealt with by the SEJ.

Modern track avoids fish plated joints after every single rail. All over the world we have long welded rails (long rail). The longitudinal movement of long rails gets attested by the resistance offered by the sleepers and their fastenings. The resistance offered by sleepers is on account of ballast packing the sleepers all-round.

It is only 100 to 140 meters length of long rail, which is enough to develop cumulative resistance offered by sleepers to be equal to maximum possible thermal force in the rail. This makes clear that it is only 100-140 meters of long rails at either of the ends which can expand/contract while the rest of long rail does not move.

To accommodate the expansion/contraction of the end 100-140meter portion, expansion arrangements are provided on either end of the long rail called, switch expansion joints (SEJ).
According to an aspect of the invention, a switch expansion joint for use in a railway track is installed at the end of the long welded rails(LWR) to accommodate longitudinal movements in the breathing length due to temperature variation. This improved switch expansion joints(ISEJ/JSEJ) is a new hope switch expansion joint which comprises of incoming main rail, herein called as tongue rail, provided with cut followed by its machined portion which expands / contracts longitudinally accommodating movements in the breathing length. Immediately after the cut in the tongue rail is, the inner stock rail of reduced head width, acting as an accomplice to the tongue rail & housed along with the machined portion of tongue rail. This arrangement of inner stock rail and the tongue rail provided with groove at gauge face makes the wheel tyre to pass through without any attack on the cut & machined portion for expansion arrangements on gauge face side (1) of the tongue rail wherein the machined portion of tongue rail (2) of appropriate length starts and terminates within the very first sleeper (3) and machined portion of tongue rail does not go out of the very first sleeper (3). On the termination of machined portion of tongue rail starts outer stock rail, of same cross section as of machined portion of tongue rail, housed along with inner stock rail.

The present invention relates to a device having a Prototype using Tongue Rail of 8.5 curve Switch with the gap for double expansion & contractions on both side of LWR.

The basic premise of this design is also based on Tongue Rails housed in Stock Rail of which the receptivity has never been an issue. Guidance of wheel in this design is without any cut on gauge face & non-gauge face, ensures smooth transfer of load from tongue rail to stock rail & limited lateral load. Since the SEJ is inspired and highly modified version of 1 in 8.5 switch, the lateral load on same is very minimal as its without any curvature i.e. Tongue Rail is straight. The tip of tongue rail is easily housed and rests inside stock rail which makes the wheel tyre to pass through without any attack. The lateral load on either of rails are same as LWR running rail. During vertical loading, tongue rails vertical movement is not possible (fixed) which makes SEJ more stable. Another reason for its higher stability is that its tongue rail non Gauge face side (machining side) rests inside stock rail and has its full support.
The design provides complete head width of 72 mm against the impact of wheel tyre upto width of 46mm. Tongue rails are maintenance free as expansion/contraction is of stock rail i.e. TWR on both sides. These are very well established features of this system.
It has been found that both these Improved SEJs has poor reliability so has been ordered to stop the procurement. Studies are going on to search the reasons for poor reliability of both single gap & double gap ISEJs.

According to another aspect of the invention, the present invention relates to a development of the improved switch expansion joints named as JSEJ by making provisions of both the cuts & machined portions for expansion arrangements now on gauge face side (1). No machining whatsoever has been done on non-gauge face side. The cut as proposed now on gauge face side for expansion/ contraction in the present invention ISEJ design (JSEJ) is similar to cut on non-gauge face side in the unreliable designs of single gap ISEJ/double gap ISEJ.
This design of JSEJ is attached with all relevant rail sections in simplified form so as to appreciate the machining in tongue rail & fabricated stock rail.
In this design, named as JSEJ, the head width of tongue rail (2) of approaching long rail on either end is machined to 44-45 preferably 44.75 mm to provide cut for an appropriate length (refer fig. 1) on gauge face side (1) with its accomplice inner stock rail (5) of 27-28 preferably 27.25 mm of head width (refer fig. 2). The machined portion of tongue rail (2) of appropriate length starts and terminates within the very first sleeper (3) (ref fig. 3) i.e. machined portion of tongue rail does not go out of the very first sleeper (3). The gauge face after the cut in the tongue rail gets shifted from tongue rail to inner stock rail (5) (ref fig. 3) This provision of inner stock rail avoids direct impact of lateral load on cut & machined portion of tongue rail. Immediate bolting of inner stock rail (5) & outer stock rail (4) after the very first sleeper (3), gets possible because movement of tongue rail is now confined within this sleeper (ref fig. 3). The immediate bolting after the first sleeper in JSEJ strengthens the lateral restrain of all three rails within the pair of brackets on the very first sleeper.
The inner stock rail of 27-28 mm head width & outer stock rail of 44-45 mm head width emerges together from the very first sleeper and bolted (ref fig. 3), as mentioned above, to form fabricated stock rail immediately after the first sleeper (ref fig. 3). Fabricated stock rail of around Six meters is thus of total head width of 72mm with double web, bridging the assembly on only sleeper for expansion arrangement on either ends.
Both tongue rail (2) are incoming running rails on either side of the assembly are laid both for left hand and right hand. Gauge face (1) of both the incoming tongue rails & gauge face of the fabricated stock rail provide gauge face for the flange of wheel to negotiate in their respective lengths.
The advantages of the present invention are listed herein below:
(i) No bolting of tongue rail (2) & its accomplice rail (outer stock rail in double gap ISEJ/ Gap avoiding rail in Single gap ISEJ) is possible in single gap ISEJ or double gap ISEJ after the first sleeper. Field people confirm, these rails to have unpredictable behavior till end of the tongue rail.
In the present invention ISEJ/JSEJ, situation of unpredictable behavior of machined portion of tongue rail on above account gets fully eliminated (ref fig. 3)
(ii) In JSEJ, after the cut/design arc, on shift of gauge face (1) to inner stock rail, no chance of jumping of wheel on the inner stock rail (5) because of part of wheel tyre still moving on the machined portion of tongue rail after the cut (ref fig. 3).
(iii) In JSEJ, at the end of tongue rail, no chance of jumping of wheel from tongue rail on the outer stock rail because inner stock rail keeps providing the continuity of gauge face (ref fig. 3).
(iv) In JSEJ, the inner stock rail avoids direct impact of lateral load on design arc & machined tongue rail whereas there is direct impact of lateral load on design arc & machined tongue rail in existing both the ISEJs.
(v) In JSEJ, machining has been restricted to gauge face (1) side.
(vi) In JSEJ, brackets (6 & 7) on both sides i.e., gauge face as well as on non-gauge face (8) are head and web fit. It controls any tendency for dancing of both inner stock rail and tongue rail (ref fig. 4)
(vii) In JSEJ, bolting is done immediately within 5 inches of the first sleeper, leaving no Stock rail in isolation which can behave independent of each other (ref fig. 3)
(viii) In JSEJ, bolting immediately after sleeper 22/11 creates imprint of fabricated stock rail on outer & inner stock rails before these stock rails leave the only pair of bracket.
(ix) In JSEJ, sharing of load between inner & outer stock rail start, just like fabricated stock rail, before these two stock rails come out of the only pair of bracket (ref fig 3).
(x) The presence of isolated rails in between pairs of brackets (6 & 7) in existing ISEJ’s, play adverse role in exercising the required lateral strain by the brackets.
Whereas, in the present invention(JSEJs), immediate bolting after the only pair of bracket as elaborated above, strengthens the lateral restrain of all three rails within this bracket. Thus all 3 rails (tongue rail, Inner stock rail & Outer stock rail ) inside bracket in JSEJ tend to behave as one cohesive unit- full bodied & robust to share/apportion the vertical and lateral load (ref fig. 3 & 4).
(xi) In JSEJ, head width of Inner stock rail is 27-28 preferably 27.5mm and head width of outer stock rail is 44-45 mm. The advantage is the eccentricity for inner stock rail & for outer stock rail are very less because of center of webs of inner stock rail at outer stock rail have got closure to the gauge face. This ensures more uniform loading of both the stock rails in JSEJ design as compared to T6922 which had predominant failure of bolts.
(xii) In JSEJs, there is no foreseeable indeterminate maintenance issues. Further, maintenance issues in JSEJs get limited to one sleeper only. Whereas, in existing ISEJs -single gap or double gap, the spanning of tongue rail & truncated rails (outer stock rail/ gap avoiding rail) to behave independent of each other till end of tongue rail, leads to uncertainty of attention in handling maintenance issues to our satisfaction.
The present invention ISEJ/JSEJ essentially comprises of the following items:
a. Tongue Rail L.H
b. Tongue Rail R.H
c. Stock Rail Inner
d. Stock Rail Outer
e. C.I Chair
f. C.I Chair
g. M.S Bracket (Outside) NGF
h. M.S Bracket (Inner side GF)With Packing PCS
i. Angle Tie
j. Tee Head Bolt
k. Tee Head Bolt
l. Grooved Rubber Sole Plate
m. Grooved Rubber Sole Plate
n. Plate Screw
o. Plate Screw
p. Hardened Washer (Plain)
q. Hardened Washer (Grooved)
r. H.T.S Bolt With Nut
s. S.C.S Washer

BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be explained in more detail with reference to the drawings accompanying the specification, wherein-
Fig.1 shows a design of tongue rail with gauge face side
Fig.2 shows the inner stock rail
Fig.3 shows the fixing of tongue rail with stock rail in one sleeper
Fig.4 shows the assembly of tongue rail, stock rail, bracket, bolt, rubber pad, C.I. Chair on one sleeper

DETAILED DESCRIPTION OF THE DRAWINGS
Figure 1 shows the head width of tongue rail (2) of approaching long rail machined to 43-45 mm to provide cut for an appropriate length on gauge face side (1).
Figure 2 shows the inner stock rail (5). The cut/design arc on gauge face (1) to inner stock rail, leaves no chance of jumping of wheel on the inner stock rail (5).
Figure 3 shows the machined portion of tongue rail (2) of appropriate length starts and terminates within the very first sleeper (3) i.e. machined portion of tongue rail does not go out of the very first sleeper (3). The gauge face after the cut in the tongue rail gets shifted from tongue rail to inner stock rail (5). The machined portion of tongue rail and inner stock rail hugging each other starts and terminates within the only sleepers (3) at either ends of fabricated stock rail. This provision of inner stock rail avoids direct impact of lateral load on cut & machined portion of tongue rail. Immediate bolting of inner stock rail (5) & outer stock rail (4) after the very first sleeper (3), gets possible because movement of tongue rail is now confined within this sleeper. The immediate bolting after the first sleeper strengthens the lateral restrain of all three rails within the pair of brackets on the very first sleeper. The load is shared between inner & outer stock rail, just like fabricated stock rail, before these two stock rails come out of the only pair of bracket.

Figure 4 shows the assembly of tongue rail, stock rail, bracket, bolt, rubber pad, C.I. Chair on one sleeper. The gauge face (1), tongue rail(2), sleeper(3),Tee head Bolt on gauge face(10), Tee head bolt(11), chair rubber pad(9), C.I.chair (8), the brackets (6 & 7) arranged on both sides i.e., gauge face as well as on non-gauge face (8) are head and web fit. It controls any tendency for dancing of both inner stock rail and tongue rail. Immediate bolting after the only pair of bracket as elaborated above, strengthens the lateral restrain of all three rails within this bracket. Thus all 3 rails (tongue rail, Inner stock rail & Outer stock rail) inside bracket in JSEJ tend to behave as one cohesive unit- full bodied & robust to share/apportion the vertical and lateral load. The features with reference 3,9, 10,11 are known features.
The invention has been described with reference to the drawings but the applicant reserves the right to explain further the invention if demanded within the scope as described in the disclosure.

,CLAIMS:
We Claim:
1. An improved Switch expansion joints for use in a railway track installation at either ends of long welded rails(LWR) to allow longitudinal movements owning to its designs, comprising of a pair of fabricated stock rails and a pair of tongue rails at either ends wherein the arrangement of cut and machined portion for expansion and hugging respectively falls at gauge face side and the machined portion of tongue rail and inner stock rail hugging each other starts and terminates within only sleepers (3) tightened with brackets (6 & 7) on gauge face as well as on non-gauge face (8) which are head and web fitted at either ends of fabricated stock rail i.e. outer stock rail(4) or inner stock rail(5) to controls any tendency for dancing of both inner stock rail and tongue rail of ISEJ.
2. An improved Switch expansion joints as claimed in claim 1, wherein the head width of tongue rail (2) of approaching long rail on either end is machined to 44 -45mm to provide cut for an appropriate length on gauge face side (1) with its accomplice inner stock rail (5) of 27-28 mm of head width.
3. An improved switch expansion joints as claimed in claim 1, wherein the gauge face due to the cut in the tongue rail gets shifted from tongue rail to inner stock rail (5) making the provision of inner stock rail avoiding direct impact of lateral load on cut & machined portion of tongue rail.
4. An improved switch expansion joints as claimed in claim 1, wherein immediate bolting of inner stock rail (5) & outer stock rail (4) after the very first sleeper (3), gets possible because movement of tongue rail is now confined within this sleeper.
5.An improved switch expansion joints as claimed in claim 1, wherein bolting is done immediately within 5 inches of the first sleeper, leaving no Stock rail in isolation which can behave independent of each other.

6.An improved switch expansion joints as claimed in claim 1, wherein bolting immediately after sleeper 22/11 creates imprint of fabricated stock rail on outer & inner stock rails before these stock rails leave the only pair of bracket.
7.An improved switch expansion joints as claimed in claim 1, wherein sharing of load between inner & outer stock rail start, just like fabricated stock rail, before these two stock rails come out of the only pair of bracket.
8. An improved switch expansion joints as claimed in claim 1, wherein immediate bolting after the only pair of bracket as elaborated above, strengthens the lateral restrain of all three rails within this bracket making all 3 rails (tongue rail, Inner stock rail & Outer stock rail) inside bracket in JSEJ tend to behave as one cohesive unit- full bodied & robust to share/apportion the vertical and lateral load.
9. An improved switch expansion joints as claimed in claim 1, wherein the inner stock rail of 27-28 mm head width & outer stock rail of 44-45mm head width emerges together from the very first sleeper and bolted to form fabricated stock rail immediately after the first sleeper.
10. An improved switch expansion joints as claimed in claim 1, wherein fabricated stock rail of around six meters is of total head width of 71-72mm with double web, bridging the assembly on only sleeper for expansion arrangement on either ends.
11. An improved switch expansion joints as claimed in claim 1, wherein at the end of tongue rail, no chance of jumping of wheel from tongue rail on the outer stock rail as inner stock rail keeps providing the continuity of gauge face.